MAZAR-I-SHARIF, Afghanistan — At least 100 Afghan soldiers abandoned their posts and fled imminent capture by the Taliban by crossing the country’s border into neighboring Turkmenistan, only to face immediate expulsion, Afghan officials said on Saturday.

It was the latest in a series of insurgent attacks in the hotly contested Bala Murghab district, where an entire Afghan Army company was killed or captured on Monday. By Saturday, its defenders said the district had mostly fallen into Taliban control.

Afghan officials gave varying accounts of what happened Saturday, with some saying the soldiers would be returned to safety by Turkmenistan, and others that they had been forced back by the Turkmenistan Army into a no man’s land, a 500-yard-wide strip between border fences. And some said the soldiers had been forced back into Taliban hands by day’s end.

Saleh Mohammad Mubarez, the commander of the Afghan local police in the district, said that 140 soldiers from the Afghan Border Police, a military unit, had fled toward Turkmenistan after two days of Taliban attacks on bases in the Morichaq area.