"They strongly supported calls for a full ceasefire starting on September 1 due to the start of a new school year… They underscored the importance of continued ceasefire, citing the plight of civilians in eastern Ukraine," the statement said.
The leaders of the three countries also stressed that heavy weapons with a caliber of over 100mm should be pulled away from the line of contact as soon as possible and called the upcoming local elections in Ukraine on October 25 "an important step toward the implementation of Minsk accords," according to the statement.
In July, the four leaders agreed that artillery with a caliber below 100mm should also be pulled away from the region to forward the peace process.
According to the UN estimates, more than 6,800 people have been killed in the Ukrainian conflict since its start in spring 2014.