The Kyrgyz-Tajik borders have experienced violence over years. (Reuters)

Against the background of an escalation on the border between Kyrgyzstan and Tajikistan, Secretary General of the Collective Security Treaty Organization (CSTO) Stanislav Zas held phone calls with the heads of the Kyrgyz and Tajik security councils, announced the CSTO.

"On September 16, 2022, CSTO Secretary General Stanislav Zas held telephone conversations with ... [the heads of the Kyrgyz and Tajik security councils] in connection with the sharp aggravation of the situation on the Kyrgyz-Tajik border, which occurred this morning," the CSTO wrote on Telegram.

The two sides confirmed the need for an urgent ceasefire on the border and negotiations to conclude a peaceful resolution for the conflict, according to the organization.

Earlier today, Tajik forces opened fire again on several of Kyrgyzstan outposts on Friday, as a result of tension between the Russian allies after a short confrontation earlier this week.

Along the entire length of the border, Kyrgyz border guards returned fire as clashes took place, with the service adding that Tajik forces were using tanks, armored personnel carriers, and mortars.

Tajikistan accused Kyrgyzstan forces of using "heavy weaponry" to shell one of its outposts and seven villages, in which a civilian was killed and three were injured, according to authorities in the Tajik city of Isfara.

The provocation began when Tajik patrol guards were asked by Kyrgyz troops to relinquish "combat positions", Russian media reported, and the Kyrgyz border service issued that request as a result of the provocative combat positions that the Tajik side took up on the uncontrolled section of the border.

The poorly demarcated border witnesses clashes between the two former Soviet republics frequently, which usually tend to de-escalate quickly, although last year they almost led to an all-out war. The Polish mission to the Organization for Security and Co-operation in Europe (OSCE) reported that the organization issued calls for both countries to reimplement a ceasefire.

Both countries host Russian military bases and have cordial and close ties with Moscow, which called for a cessation of hostilities this week.