Almost 30 people have been reported killed and dozens injured in clashes on the Kyrgyzstan-Tajikistan border.
Fighting regularly flares up between the two former Soviet states, whose border has been disputed since the collapse of the USSR.
A fresh skirmish which began earlier in the week continued on Friday, despite the two countries agreeing a ceasefire.
Both sides blame the other for beginning the violence and breaching the ceasefire.
Some 24 people in Kyrgyzstan have so far been killed, the Kyrgyz health ministry said on Friday.
Earlier reports from Tajikistan said at least three people had been killed there.
Almost 20,000 people have fled their homes to avoid the violence, a regional branch of the Red Cross reported.