Ukrainian President Petro Poroshenko and his Russian counterpart Vladimir Putin are in Belarus for talks Tuesday.
The leaders are taking part in a summit of the Russia-led customs union, alongside representatives from the European Union.
The two had met briefly in June.
Since then, Ukrainian forces have gained the upper hand against pro-Russian rebels fighting for control over an area in eastern Ukraine.
Ukraine said Monday, its security services had captured 10 Russian servicemen in the area and also clashed with 10 tanks and two armored personnel carriers from Russia.
Ukraine has accused Moscow of sending its troops into the country -- a claim the Kremlin denies.
Over 2-thousand people have died in fighting since Russia annexed Crimea in March.
In a separate development, Poroshenko dissolved parliament on Monday and announced elections for October 26th .
The president said that many of the current MPs were supporters of ousted President Viktor Yanukovich, and added that the majority of Ukrainians want a new parliament.
Kim Min-ji, Arirang News.