NICOSIA (Reuters) - German foreign minister Heiko Maas criticized Turkey for sending a survey vessel back into controversial waters of the eastern Mediterranean, calling the unilateral move a blow to efforts to start negotiations in the conflict. “Turkey’s back and forth between escalation and a policy of detente has to stop,” Maas said after meeting his Cypriot counterpart Nikos Christodoulides in Nicosia on Tuesday. “It is up to Turkey to create the conditions for talks.” Maas, whose trip was supposed to mediate and reduce tensions in the region, said he had deliberately left Ankara out of his itinerary. “My decision only to travel to Nicosia and Athens today is owing to the current developments that we have been talking about,” he added. On Monday, the Turkish ship Oruc Reis set sail to carry out seismic surveys in the eastern Mediterranean, prompting Greece to issue a furious new demand for European Union sanctions on Ankara in a row over offshore hydrocarbon exploration rights.