BERLIN (Reuters) - Foreign Minister Heiko Maas said on Tuesday that Germany would not let up in its efforts to de-escalate the conflict between Russia and Ukraine and it was more important than ever to reinvigorate talks between Germany, France, Russia and Ukraine.

Ukraine and Russia have traded accusations after Russia fired on three Ukrainian ships then seized them. The confrontation prompted Ukraine to introduce martial law in some areas, citing the threat of a Russian land invasion.