Al Arabiya News Channel reported that Islamic State of Iraq and al-Sham (ISIS) militants took control of the Syrian side of the Al Waleed border crossing that connects Syria with Iraq. "Earlier on Thursday, a fire erupted at the crossing after Iraqi troops blocked access from their side after Syrian regime forces had withdrawn from Al Waleed," the news channel said. Reuters quoted an ISIS militant as saying that the group had taken control of the crossing, which is a 240 km drive from Palmyra, known as Tadmur in Arabic. The group already controls the other parts of the border including the Syrian province of Deir al-Zor and the Iraqi province of Anbar. The only part of the border that is not controlled by ISIS is in the north, where armed Kurdish militias are active and have repelled ISIS attacks in the last months. The British-based Syrian Observatory for Human Rights, a group that monitors the civil war in Syria, also confirmed that the troops loyal to the Syrian regime withdrew from the area.The capture of the last part of the border came after ISIS seized full control of the ancient Syrian city of Palmyra on Thursday. The U.N. human rights office in Geneva said that the residents of Palmyra have been prevented from leaving the city. One resident who owns a shop near Palmyra's museum told the New York Times that his family was unable to leave the area. "The government is not allowing us," he said. U.N. Human Rights spokeswoman Ravina Shamdasani said, "ISIS is conducting door-to-door searches. At least 14 civilians are reported to have been executed by ISIS in Palmyra this week." It is estimated that 70,000 civilians live in the city.On the Iraqi side ISIS has expanded its control areas after capturing the city of Ramadi in Anbar province. While Iranian-backed Shiite militias claimed that they have repelled ISIS attacks near Ramadi, AP reported that ISIS militants have seized another town in Iraq's western Anbar province according to a tribal leader. Sheikh Rafie al-Fahdawi said the small town of Husseiba fell overnight when police and tribal fighters withdrew after running out of ammunition. "We have not received any assistance from the government. Our men fought to the last bullet and several of them were killed," he told AP in a telephone interview. Al-Fahdawi said that with the fall of Husseiba, the militants have come closer to the strategic Habbaniyah military base, which is still held by government forces. "The situation is very critical. The militants are about 5 kilometers from Habbaniyah base, which is now in great danger," he said. "A day earlier, ISIS militants captured the Iraqi side of a key border crossing with Syria after Iraqi government forces pulled out. The fall of the al-Walid crossing, also in Anbar, will help the militants to shuttle weaponry and reinforcements more easily across the Iraqi-Syrian border," AP reported.In response to the rapid advance of ISIS in Iraq, Iran has, reportedly, deployed tanks near the Iraqi border to send in case of emergency and offered to help military advisers. While the Iraqi government welcomes the Iranian aid and presence, the U.S. is concerned that the Shiite groups may fuel the sectarian tension. The Obama administration, which has been criticized for being ineffective in the fight against ISIS, decided to deliver 200 anti-armor weapons to Iraq next week. An expedited shipment of 2,000 lightweight shoulder-fired weapons, intended to help the Iraqi army stop ISIS's increasingly effective use of car bombs, should arrive in Iraq as soon as next week, the Pentagon said Thursday. "The shipment is among a variety of weaponry and equipment the U.S. agreed to send to Iraq on an expedited basis after Iraqi Prime Minister Haider al-Abadi visited Washington in April to plead for more help in fighting the extremists. Col. Steve Warren, a Pentagon spokesman, said the shipment of shoulder-fired AT-4 weapons was not in response to the fall of Ramadi over the weekend, although the militants' effective use of enormous car bombs there put the spotlight on Iraqi army deficiencies and prompted the White House to consider ways of strengthening U.S. support for Iraq. The AT-4 is relatively lightweight and is designed to penetrate armor, making the weapon useful in stopping what the military calls vehicle-borne improvised explosive devices, or car bombs, before they approach their intended target. In an update to the overall cost of U.S. military involvement in Iraq and Syria, Warren said that as of April 9 the U.S. had spent $2.1 billion since it began bombing in Iraq in August," Reuters reported.