"The Tajik side is using mortars and grenade launchers," in the attacks, Kyrgyzstan's national security committee said in a statement.

The statement described the situation at the border as "tense", after an incident earlier in the day saw citizens of Tajikistan block a strategic road in the region.

The road was later reopened, "but the situation worsened due to the use of weapons and fire by the Tajik side on the border units of" Kyrgyzstan, the statement said.

Clashes between communities over land and water along the pair's long-contested border are regular occurrences, with border guards often getting involved.

But the shooting that broke out last year between the two militaries, which left more than 50 people dead, was the heaviest fighting in years and raised fears that it might escalate into a wider conflict.