Four Ukrainian soldiers killed as fighting tests truce

KIEV (Reuters) - Four Ukrainian servicemen have been killed and 14 wounded in fighting with pro-Russian rebels in the past 24 hours, the Ukrainian military said on Thursday, as a new wave of violence rekindled concerns a ceasefire deal could be crumbling.

A notable increase in military and civilian casualties in the past two weeks has prompted the leaders of France and Germany, who helped broker the six-month-old truce, to arrange new talks with President Petro Poroshenko to discuss how to preserve the peace.

Ukrainian military spokesman Oleksander Motuzyanyk reported renewed rebel shelling of government positions near the separatist-held city of Donetsk and mortar fire in villages near the strategic Kiev-controlled port city of Mariupol.

"In this area the enemy does not engage in direct fighting with the Ukrainian army, but regularly fires chaotically from howitzers and GRAD multiple rocket launchers," he said.

Separatist officials accused Ukrainian troops in turn of shelling rebel territory, including residential areas.

On Wednesday, NATO warned Russia, which the West accuses of supporting the separatists with equipment and fighters, that any attempt by the rebels to take more of Ukraine's territory would be unacceptable.

Poroshenko will meet German Chancellor Angela Merkel and French President Francois Hollande in Berlin on Monday to discuss the latest escalation in the conflict, which has killed over 6,500 since erupting in April 2014.

(Reporting by Natalia Zinets; Writing by Alessandra Prentice; Editing by Richard Balmforth and Clelia Oziel)