Russian President Vladimir Putin called on both countries to resolve their differences using ‘peaceful, political and diplomatic means’.
Tajikistan said that 35 of its citizens were killed in the latest border clashes with Kyrgyzstan, raising the overall death toll to at least 81.
On its Facebook page, the Tajik foreign ministry reported 35 people dead including civilians, women, and children.
A further 139 people had been wounded in the fighting on the southwestern border, it said.
The previous toll given by the ministry was 24 dead.
Meanwhile, the number of deaths on the Kyrgyz side rose to 46, making it the worst flare-up between the two Central Asian countries in years.
Kyrgyzstan said nearly 136,000 residents were also evacuated from villages near Tajikistan.
Russian President Vladimir Putin on Sunday called for “no further escalation” between Kyrgyzstan and Tajikistan.
In phone calls with the leaders of the Central Asian nations, Putin also urged them to “take steps to resolve the situation as soon as possible by exclusively peaceful, political and diplomatic means”.
Both former Soviet Union countries are now part of the Russia-led Collective Security Treaty Organisation (CSTO) but they regularly have escalating tensions.
On Friday, the two sides agreed to a ceasefire but since then the fighting continued with both sides accusing each other of breaching the agreement.
After more clashes on Saturday, the night passed “quietly, without incidents” the Kyrgyz authorities said on Sunday morning.
“The country’s leadership is taking all measures to stabilise the situation, prevent attempts of escalation … in a peaceful way,” they added.
On Sunday afternoon, the Kyrgyz authorities issued a statement saying the situation at the border “remains calm, trending towards stabilisation”.
United Nations Secretary-General Antonio Guterres called on the leadership of both sides “to engage in dialogue for a lasting ceasefire”, said a spokesman.
Border disputes have dogged the former Soviet republics through their three decades of independence. Around half their 970-kilometre (600-mile) border is still to be demarcated.
Unprecedented clashes between the two countries happened in 2021, killing at least 50 people and raising fears of a wider conflict.