More than 1,000 Afghan troops fled into neighbouring Tajikistan in the early hours of Monday after clashes with the Taliban, the Central Asian country's national security committee said.

Taliban militants have launched several major offensives in northern Afghanistan in recent weeks as US and international troops withdraw from the country, including seizing its main crossing into Tajikistan last month.

On Monday, Tajikistan's national security committee said that 1,037 Afghan government troops had fled into the ex-Soviet country "in order to save their lives" after clashes with the Taliban during the night.

"Taking into account the principle of good neighbourliness and adhering to the position of non-interference in the internal affairs of Afghanistan, the military personnel of the Afghan government forces were allowed to enter Tajik territory," the committee said in a statement distributed by Tajikistan's state information agency Khovar.

It said the Taliban had taken "full control" of six districts of the Badakhshan province bordering Tajikistan in Afghanistan's northeast.

Several hundred Afghan troops had already crossed into Tajikistan after the Taliban unleashed its onslaught in early May.

The militants have seized dozens of Afghanistan's districts, raising fears that that the Afghan military will collapse once US and international troops complete their withdrawal from the country in September.

US President Joe Biden has ordered the departure of all US forces from Afghanistan by this year's 20th anniversary of the September 11 attacks that triggered the invasion.