Afghanistan’s former President Hamid Karzai has blasted the US for dropping its largest non-nuclear bomb in the Asian country, saying Washington is using his country as a “testing ground” for its new weapons.

“I vehemently and in strongest words condemn the dropping of the latest weapon, the largest non-nuclear #bomb, on Afghanistan by US military,” Karzai wrote on Twitter on Thursday, referring to the strike that was carried out earlier in the day.

Karzai, who became Afghanistan’s first president under an agreement largely negotiated by Western countries after the US-led invasion of Afghanistan in 2001, further called on his country to “stop” the US.

“This is not the war on terror but the inhuman and most brutal misuse of our country as testing ground for new and dangerous weapons. It is upon us, Afghans, to stop the #USA.”

Earlier on Thursday, the US military said it had conducted a strike on a Daesh tunnel complex in Achin district in Afghanistan’s Nangarhar province.

A military statement said a GBU-43/B Massive Ordnance Air Blast (MOAB) bomb had been dropped from a US aircraft in the strike. It claimed that US forces had taken every precaution to avoid civilian casualties with this strike, without elaborating.

Afghan officials said on Friday that the US strike had killed at least 36 suspected Daesh terrorists, smashing a deep tunnel complex in the area. They said no civilian casualties had been caused.

“As a result of the bombing, key Daesh hideouts and a deep tunnel complex were destroyed and 36 fighters were killed,” Afghanistan’s Defense Ministry said in a statement.

US President Donald Trump, meanwhile, described the bombing as “very, very successful.”

Achin district governor Esmail Shinwari said the bomb landed in the Momand Dara area of Achin district. “The explosion was the biggest I have ever seen. Towering flames engulfed the area.”

The huge bomb — delivered via an MC-130 transport plane — has a blast yield equivalent to 11 tonnes of TNT, and been designed to intimidate the enemy as well as to clear broad areas, according to the US military.