MAZAR-I-SHARIF, Afghanistan — The Taliban carried out the biggest known capture of Afghan soldiers of the war, taking 150 prisoners after they chased units into neighboring Turkmenistan and that country forced them back, Afghan officials said on Sunday.

The operation took place in the northwestern Afghan province of Badghis, and brought to 190 the number of soldiers captured by insurgents in the hotly contested district of Murghab — with 16 more soldiers killed — in less than a week.

Last Monday, an entire Afghan Army company was killed or captured there. By Saturday, its defenders said the district had fallen mostly into Taliban control, though Afghan forces were still holding the district’s government center.

The latest capture was perhaps the biggest setback for the Afghan security forces since a Taliban offensive in August in the southeastern city of Ghazni killed as many as 200 soldiers and police officers, but few prisoners were taken then. The biggest recent capture of soldiers by the Taliban was about 50 who surrendered after a siege of their base, known as Chinese Camp, in Faryab Province, also in August.