Talks were starting in Brussels on Tuesday to try to end the 13-year conflict between Moldova and its breakaway Trans-Dniester region in the former Soviet Union.
By Helen Fawkes
BBC correspondent in Kiev, Ukraine
Although not internationally recognised, the Trans-Dniester region declared itself to be independent just before the collapse of the USSR.
Hundreds of people have died as a result of the dispute.
Peace talks broke down last year and the mediators aim to reopen dialogue between Moldova and the region.
Over the next two days officials from Ukraine, Russia and the Organisation for Security and Co-operation in Europe (OSCE) will discuss ways of resolving the conflict.
The mediators will also examine the proposals put forward by Moldova and Trans-Dniester earlier this month.
According to the OSCE, these talks are an attempt to restart the peace negotiations which stalled last November when the Moldovan president refused to sign a Russian-backed peace plan.
Trans-Dniester, in eastern Moldova, declared independence in September 1990, sparking the fighting which left hundreds dead.
The introduction of Russian peacekeepers two years later brought an end to the violence.
But the continued presence of Russian troops in Trans-Dniester, along with thousands of tons of Soviet weapons, has been one of the most contentious issues in the discussions.
It is hoped that at the end of these latest talks a date will be announced when peace negotiations between Moldova and Trans-Dniester can resume.