National security advisor Hamdullah Mohib, who was in Moscow on Monday for talks with senior security officials, told media in an interview that government forces had not expected the Taliban offensive but would “absolutely, definitely” counterattack.
Russia operates a military base in Tajikistan, a former Soviet republic bordering Afghanistan.
Russia’s foreign ministry said separately on Monday that the Russian consulate in the city of Mazar-i-Sharif in northern Afghanistan was suspending its work because of security concerns.
It comes after more than 1,000 Afghan troops fled into neighbouring Tajikistan after being defeated in clashes with the Taliban.
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.
Reports say while many troops have fled, others have chosen to drop their arms and surrender to the Taliban.
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.