KABUL — More than a thousand Afghan government forces crossed the border into neighboring Tajikistan in the early hours of Monday morning following clashes with Taliban militants, Tajik border forces said in a statement published by the Khovar news agency. The crossings of the Afghan troops underscore a rapidly deteriorating situation in the country as foreign troops near a complete withdrawal after 20 years of war in Afghanistan and with peace negotiations stalled. Hundreds of Afghan security force members have fled swift Taliban advances in the north but Monday"s retreats were the largest confirmed, coming just two days after the United States officially vacated its main base in Afghanistan as part of a plan to withdraw all foreign troops by Sept. 11. The Taliban took over six key districts in the northern province of Badakhshan, which borders both Tajikistan and China, after which 1,037 Afghan servicemen fled across the border with Tajikistan"s permission, its border guard service said. Tajikistan"s national security committee said that 1,037 Afghan government troops had fled into the ex-Soviet country "to save their lives" after clashes with the Taliban during the night. "Taking into account the principle of good neighborliness and adhering to the position of non-interference in the internal affairs of Afghanistan, the military personnel of the Afghan government forces was allowed to enter Tajik territory," said the statement, published by Tajikistan"s state information agency. — Agencies