Fighting has raged across several provinces of Afghanistan, but Taliban insurgents have primarily focused on a campaign across the northern countryside, seizing scores of districts in the past two months.
Tajikistan has called on members of a Russian-led military bloc to help it deal with security challenges emerging from neighbouring Afghanistan, Russian RIA news agency reported, as Taliban and Afghan government forces continued fighting in northern provinces.
Tajikistan made its appeal for help to the Collective Security Treaty Organisation (CSTO) on Wednesday.
The CSTO is a post-Soviet security bloc led by Russia which includes the Central Asian countries of Kazakhstan, Tajikistan and Kyrgyzstan as members.
"Given the current situation in the region, as well as the remoteness and mountainous terrain of some parts of the border with Afghanistan, dealing with this challenge on our own seems difficult," the RIA news agency quoted Hasan Sultonov, the Tajik representative at CSTO, as saying.
The security situation in Afghanistan has rapidly deteriorated as foreign troops withdraw after 20 years. In recent days hundreds of Afghan servicemen have crossed the border with Tajikistan in response to advances by the Taliban fighters.
Tajikistan accepts 1,000 refugees
Tajikistan has taken in more than 1,000 civilian refugees fleeing the violence in Afghanistan's Badakhshan province across the border, the government of Tajikistan's Gorno-Badakhshan province said on Wednesday.
The announcement was the first official statement from Tajikistan confirming that fighting in northern Afghanistan was provoking a fresh wave of civilian exodus from the area.
The refugees, most of them women, children, and elderly people, have been placed in "safe locations", it said in a statement, adding that the authorities were in talks with United Nations agencies and the Aga Khan Health Services agency regarding the provision of food and healthcare for them.
Tajikistan has also temporarily taken in hundreds of Afghan servicemen who retreated from their positions in northern provinces where most of the territory appears now to be under Taliban control.
Afghan troops flee by hundreds
More than 1,000 Afghan troops fled into neighboring Tajikistan on Monday.
"We had to abandon our base because there was no coordination or interest among our commanders to counter the attack," said one of the soldiers, Mohammad Musa.
But Mohib said the soldiers who fled were returning and rejoining the security forces.
"They may have abandoned their posts because they ran out of ammunition or they ran out of supplies, but by no means has anyone defected to the Taliban," he said.
Russia says ready to help
Also on Wednesday, Russian Foreign Minister Sergey Lavrov voiced concern over the "swiftly degrading situation" in Afghanistan.
Speaking at a news conference in Laos' capital Vientiane, Lavrov said Russia will do its utmost, including using the Russian military bases on the border between Tajikistan and Afghanistan, to prevent any aggressive raids against its allies.
The minister added that Russian President Vladimir Putin had a conversation with leaders of Tajikistan and Uzbekistan as well as other Central Asia partners about the Afghanistan issue and that Russia remains committed to its obligations under the Collective Security Treaty, suggesting military help in case one of the signatories are attacked.
"Obligations within the CSTO remain in full force, the representatives of the secretariat visited the border area between Afghanistan and Tajikistan and assessed the situation there, and they will report about things that happen there."
Tajikistan mobilises 20,000 military reservists
Afghanistan's deteriorating security situation has prompted Iran and some other countries to close their consulates in the northern Afghan province of Balkh with diplomats moving to Kabul.
Putin on Monday told Emomali Rakhmon, the president of Tajikistan, that Moscow would help the impoverished former Soviet republic contend with the fallout from NATO's exit from neighbouring Afghanistan if needed.
Rakhmon has ordered the mobilisation of 20,000 military reservists to bolster his country's border with Afghanistan after more than 1,000 Afghan security personnel fled across the frontier in response to Taliban advances.