DUSHANBE, Tajikistan/KABUL: Tajikistan's president on Monday ordered the mobilisation of 20,000 military reservists to bolster the border with Afghanistan after more than 1,000 Afghan security personnel fled across the frontier in response to Taliban militant advances.

The crossings on Sunday underscored the rapidly deteriorating situation in Afghanistan, where foreign troops near a complete withdrawal after 20 years of war and with peace negotiations stalled.

Tajik President Emomali Rakhmon made a flurry of international calls to discuss the situation with allies in the region, including Russian counterpart Vladimir Putin whose country has a big military presence in Tajikistan.

Putin assured Rakhmon that Moscow would support the former Soviet republic to stabilise its border with Afghanistan if needed, both directly and through a regional security bloc, the Kremlin said in a statement.

Russia operates its largest military base abroad in the impoverished Central Asian country, where it stations tanks, helicopters and ground attack aircraft.

Tajikistan is looking into setting up camps for potential refugees from Afghanistan, government sources told Reuters earlier on Monday.