Militants launched two separate attacks on Afghan security installations killing dozens of soldiers Thursday, the latest in a series of devastating assaults this week that left more than 120 people dead and underscored spiraling insecurity.

At least 43 Afghan soldiers were killed in a Taliban-claimed assault on a military base in southern Afghanistan which saw the insurgents blast their way into the compound with at least one explosives-laden Humvee, the defense ministry said.

The militants then razed the base in the Chashmo area of Maiwand district in Kandahar province to the ground, according to the ministry.

"Unfortunately there is nothing left inside the camp. They have burned down everything they found inside," defense ministry spokesman Dawlat Waziri said.

Separately yesterday, militants besieged a police headquarters in the southeastern province of Ghazni, attacking it for the second time this week. Airstrikes have been called in to support embattled police in the ongoing assault, which has killed two security forces so far, Ghazni provincial police chief Mohammad Zaman told AFP, though that was not immediately confirmed by US Forces. Officials said the earlier assault on the headquarters, which took place on Tuesday, left 20 people dead and 46 wounded.

Thursday's attacks take the number of suicide and gun assaults on security installations this week to four and increase the total death toll to more than 120, including soldiers, police and civilians. In three out of the four assaults this week the Taliban used a Humvee vehicle as a bomb to blast their way into their targets.

US President Donald Trump vowed earlier this year to stay the course in Afghanistan, America's longest war. But the Taliban said the recent assaults were a "clear message to the Americans and the Kabul government, that they cannot scare us with their new so-called strategy."

Beleaguered Afghan security forces have faced soaring casualties in their attempts to hold back the insurgents since NATO combat forces pulled out of the country at the end of 2014. Casualties leapt by 35 percent in 2016, with 6,800 soldiers and police killed, according to US watchdog SIGAR.

The insurgents have carried out more complex attacks against security forces in 2017, with SIGAR describing troop casualties in the early part of the year as "shockingly high." The attacks included assaults on a military hospital in Kabul in March which may have killed up to 100 people, and on a base in Mazar-i-Sharif in April which left 144 people dead.