By Gabriela Baczynska and Alissa de Carbonnel
BRUSSELS (Reuters) - European Union leaders offered Ukraine more aid at a summit on Thursday after Russia's seized its ships off Crimea but calls to punish Moscow with more sanctions went unheeded for now as Berlin and Paris try to secure the release of captured sailors.
The bloc's 28 national leaders, however, decided to roll over the existing economic sanctions over Crimea's 2014 annexation by Moscow and Russia's subsequent backing for rebels in east Ukraine.
There was no consensus to step up punitive measures as sought by more hawkish governments, though the bloc agreed it was "ready to adopt measures, including to strengthen further its support" to Ukraine's southern regions.
In a sign of divisions on how to handle President Vladimir Putin's Russia, the text did not mention sanctions directly.
But the EU offered Ukraine help for its regions suffering from curtailed trade because of Moscow's actions in the Azov Sea.
"There is no justification for the use of military force by Russia," the bloc said.
The EU demanded the release of the 24 Ukrainian sailors, the return of their three vessels and free passage to all ships passing through the Kerch Strait, which controls access to the Azov Sea near Crimea.
Diplomats in Brussels said both Ukrainian and EU vessels were suffering extended waiting time to pass the narrow strait between the Russian mainland and the Moscow-annexed Crimea.
Ukrainian President Petro Poroshenko, who met EU summit chairman Donald Tusk in Brussels on Wednesday, also received reassurances from NATO's head Jens Stoltenberg.
Stoltenberg said earlier on Thursday that the Western military alliance would supply Ukraine with secure communication equipment this month - part of a 40-million-euros ($46 million) pledge to bolster Kiev's armed forces.
"Ukraine invites allies to come up with comprehensive, tough measures to respond to Russia's actions," Poroshenko told reporters after meeting Stoltenberg.
European Parliament lawmakers overwhelmingly backed a non-binding report this week calling on EU governments to introduce targeted sanctions if Moscow fails to release the Ukrainian servicemen.
Among the 28 EU states, the three former Soviet republics in the Baltics, backed by Poland, Sweden and Britain, wanted a much tougher threat of more sanctions following the new flare-up of tensions between Russia and Ukraine.
But Germany and France, which put the accent on the need to ease tensions, said the time was not right as they were negotiating with Russia to release the Ukrainian sailors.
"On possible sanctions because of the incident in the Azov Sea, there is no consensus," a German government source said. "Many question if that is reasonable."
(Additional reporting by Andreas Rinke, Writing by Alissa de Carbonnel, Editing by Richard Balmforth)