Merkel welcomed the Wednesday beginning of round-table talks aimed at shaping political dialogue, after Ukraine said its security forces had suffered a day of heavy losses.

The Ukrainian government said it was preparing to negotiate with various parties, although it said leaders of the separatist armed uprising in the eastern regions of Donetsk and Luhansk would not be invited, claiming they had "blood on their hands."

While Merkel welcomed the presence of multiple parties, she also reiterated on the eve of the talks that separatists who used violence could not be accommodated. The talks are being held under the guidance of the Organization for Security and Cooperation in Europe (OSCE).

"The more representative the round-table talks are, the better," said Merkel. "However, it is obviously also clear that people are only welcome if they can credibly show that they are prepared to reach their goals without violence."

The talks are to be co-chaired by German former diplomat Wolfgang Ischinger and either Leonid Kravchuk or Leonid Kuchma - both former Ukrainian presidents. German Foreign Minister Frank-Walter Steinmeier flew to Ukraine on Tuesday to help convene the negotiations.

Bitter losses for Kyiv

News of the talks on Tuesday came as the Ukrainian military said they had lost seven troops in an ambush by separatists, the heaviest loss of life for government forces since their offensive in the east began.

Russia has criticized the interim government's "unwillingness" to engage with the eastern breakaway leaders.

In a statement, the Kremlin demanded that the European Union and the US use their influence over the Kyiv government to begin talks with the separatists "before the May 25 election."

Analysts have said it is unlikely that a satisfactory presidential election could go ahead in both Donetsk and Luhansk. The difficulty follows a May 11 secession referendum in both regions, with the electorate being said to have voted overwhelmingly to leave Ukraine.

rc/jm (AFP, AP, dpa, Reuters)