The Ukrainian government has dispatched a convoy of buses to the besieged southeastern Ukrainian port city of Mariupol in the hopes of evacuating citizens still stuck there.

Iryna Vereshchuk, the deputy prime minister of Ukraine, said 45 buses will be sent to Mariupol on Thursday, following Russia's announcement of a temporary cease-fire for the city.

"We are doing everything possible to ensure that the buses get to Mariupol today and pick up the people who have not yet made it out of the city," Vereshchuk said in a video message. "Our military forces guarantee a complete cease-fire," she said.

The bus convoy was to carry evacuees from Mariupol to Zaporizhzhia, about 200 kilometers (124 miles) away, via the Russian-controlled city of Berdyansk.

The Red Cross said Thursday it was preparing to facilitate the safe passage of civilians from Mariupol on Friday, provided all the parties agree to the terms.

"It's desperately important that this operation takes place. The lives of tens of thousands of people in Mariupol depend on it," the International Committee of the Red Cross (ICRC) said in a statement.

Mariupol, a city on the Sea of Azov, has been surrounded by Russian troops since the beginning of March. According to Ukrainian officials, more than 100,000 people are still in the heavily destroyed city, where there is a severe shortage of food, medicines, heat and power. Before the war, almost 440,000 people lived there. Several previous civilian evacuation efforts have failed due to the inability to establish safe exit routes amid the fighting.

Vereshchuk also said that a humanitarian corridor had been established for the evacuation of people from the Russian-occupied areas of Melitopol and Enerhodar, located to the west of Mariupol.

People who have managed to flee have described the conditions in Mariupol as catastrophic, with civilians bunkered down in cellars, deprived of water, food and communication, and dead bodies littering the streets.

Late Wednesday, the Russian Defense Ministry said that a humanitarian corridor would be opened from Mariupol to Zaporizhzhia, via the Russian-controlled port of Berdyansk, from 10:00 a.m. local time (7:00 a.m. GMT) on Thursday.

"For this humanitarian operation to succeed, we propose to carry it out with the direct participation of the U.N. High Commissioner for Refugees (UNHCR) and the International Committee of the Red Cross (ICRC)," the ministry statement said.

The Russian ministry asked Kyiv to guarantee "unconditional respect" for the cease-fire through written notification to the Russian side, the UNHCR and ICRC before 6:00 a.m. (3:00 a.m. GMT) Thursday. Moscow also asked the Ukrainian army to commit to ensuring the security of the bus convoys along the designated corridor.

Since Russia started its military operation in Ukraine on Feb. 24, around 1,200 civilians have been confirmed killed, although the actual number is likely to be much higher. Another 4 million have fled the country, the U.N. estimates. The United Nations believes thousands of people have died there, many buried in unmarked graves.

Ukrainian President Volodymyr Zelenskyy continued his practice of speaking to world capitals by video link. In an address to Australia's Parliament on Thursday, he called for Canberra to impose more "powerful sanctions" against Russia and for all business with the country to be halted. He thanked lawmakers for their support but urged them to send more military help, specifically the Australian-built Bushmaster armored infantry vehicles.

Australian Prime Minister Scott Morrison hailed Zelenskyy as a "lion of democracy."

"Yes, you have our prayers, but you also have our weapons, our humanitarian aid, our sanctions against those who seek to deny your freedom and you even have our coal. And there will be more," he said.

Meanwhile, Ukraine's military general staff said Russia is planning what it calls a referendum in the occupied city of Kherson to establish a Moscow-friendly "people's republic." The move is a bid to control the southern parts of Ukraine with a "civil-military administration," the general staff said in an overnight update.

It would follow a pattern for Russia, which has recognized the separatist areas of Donetsk and Luhansk in eastern Ukraine as independent. A controversial referendum was conducted in Crimea after Russia annexed the peninsula in 2014.

Kherson, with some 300,000 inhabitants, is a strategic city as it plays a key role in the protection of the port city of Odessa in Ukraine's south.

Tough resistance by Ukrainian forces has prevented Russia from capturing any major city, including the capital Kyiv, which it assaulted with armored columns from the northwest and east. Moscow says it is now focusing on "liberating" the Donbass region.

In an early morning video address, Zelenskyy said Russian troop movements away from Kyiv and the northern city of Chernihiv were not a withdrawal but rather "the consequence of our defenders' work."

Ukraine was seeing "a buildup of Russian forces for new strikes on the Donbass and we are preparing for that," he said.

The past week has seen a Ukrainian counter-offensive, recapturing destroyed suburbs of Kyiv and strategic towns and villages in the northeast and southwest. Russia declared on Monday that it was scaling back its offensive near the capital and the city of Chernihiv in the north, in what it called a trust-building gesture for peace talks.

'Putin misled,' U.S. says

Russia says it launched a "special military operation" to disarm and "denazify" its neighbor, and that the mission is going to plan.

Western countries say the invasion was an unprovoked war of aggression, that Russia's true aim was to swiftly topple the government in Kyiv, and that its failure has been a strategic catastrophe, bringing economic ruin and diplomatic isolation.

U.S. officials have declassified intelligence that they said showed a rift between Putin and his advisors, who failed to warn him of the poor performance of his military or the economic impact of Western sanctions.

"We have information that Putin felt misled by the Russian military, which has resulted in persistent tension between Putin and his military leadership," Kate Bedingfield, White House communications director, told reporters during a press briefing on Wednesday.

"We believe that Putin is being misinformed by his advisers about how badly the Russian military is performing and how the Russian economy is being crippled by sanctions because his senior advisors are too afraid to tell him the truth."

A senior European diplomat said the U.S. assessment was in line with European thinking. "Putin thought things were going better than they were. That's the problem with surrounding yourself with 'yes men,'" the diplomat said.

Military analysts have described Russia's announcement of a focus on Donbass as an attempt to reframe its war goals to make it easier for Putin to claim a face-saving victory.

Pro-Russia separatists in eastern Ukraine have said they control almost all of the Luhansk region and more than half of the Donetsk region after Moscow made these territories its primary military goal.

"As of the morning of March 31, 2022, more than 90% of the territory of the People's Republic of Luhansk has been liberated," the foreign ministry of the self-proclaimed Luhansk People's Republics (LNR) said on Telegram Thursday. Donetsk People's Republics (DNR) leader Denis Pushilin told Tass news agency Wednesday that "around 55% to 60%" of the region's territory was under Russian control.

The leader of Russia's North Caucasus Republic of Chechnya, Ramzan Kadyrov, who has sent thousands of Chechen fighters to Mariupol, said on Telegram that "90%-95%" of the strategic port city was under Russian control.

Western sanctions imposed on Russia as punishment for its invasion have largely isolated its economy from world trade, but Moscow is still the biggest supplier of oil and gas to Europe.

The United States is considering releasing up to 180 million barrels of oil over several months from its Strategic Petroleum Reserves (SPR) to ease upward pressure on prices, two U.S. sources said. Oil prices fell more than $5 a barrel on Thursday on the news.

International Energy Agency (IEA) member countries were set to hold an emergency meeting on Friday at 12 p.m. GMT to decide on a collective oil release, a spokesperson for New Zealand's energy minister said Thursday.

Russia has demanded European payments for its gas be made in rubles by Friday, raising fears of energy shortages. Germany has warned of a possible emergency if Russia cuts supplies.

A German government spokesperson said Putin had told Chancellor Olaf Scholz on Wednesday that payments could still be made in euros to Gazprombank, a bank affiliated with the Russian gas export monopoly, which would convert the money to rubles.

However, the Russian business newspaper Kommersant said Gazprom was looking into shutting off supplies: "Gazprom ... is indeed working on an option of a complete stoppage of gas supplies to 'unfriendly countries' and is evaluating the consequences of such measures," it wrote.