ANKARA (AFP) - Turkish police Monday detained more than 40 people, including former air force and navy chiefs, in connection with an alleged military plot against the government, officials and media reports said. The police swoop came amid rising tensions between the ruling Justice and Development Party (AKP) the moderate offshoot of a banned movement and its secularist opponents. This morning our security forces began a detention process, Turkish Prime Minister Recep Tayyip Erdogan told a news conference during an official visit to Spain. As of now, more than 40 people have been detained, he said, but gave no details on who was arrested. The CNN-Turk and NTV news channels said police detained former air force chief Ibrahim Firtina, former navy chief Ozden Ornek and other high-ranking officers both retired and on active service in Ankara, Istanbul, the western city of Izmir and the northwestern city of Bursa. Those held were brought to Istanbul for questioning by anti-terror police. They included at least five other retired top officials, among them Ergin Saygun, the former First Army commander and retired admirals Ahmet Feyyaz Ogutcu and Lutfi Sancar, the reports said. CNN-Turk said army chief Ilker Basbug postponed a three-day official trip to Egypt bacuse of the operation. There was no comment on the detentions either from police or prosecutors who ordered the arrests. Both Firtina and Ornek were linked to a purported 2003 plot to discredit the AKP government which was revealed by the liberal Taraf daily in January. The plan, codenamed Sledgehammer, involved bombing two Istanbul mosques and escalating tensions with Greece by forcing Greek jets to down a Turkish plane over the Aegean Sea in a bid to show the government as inept, according to documents obtained by Taraf. The Turkish army said the documents were discussed in a seminar on war-time contingency plans, but denied they represented a coup plot. Operation Sledgehammer was the latest in a series of purported military plots, mostly revealed by pro-government media, aimed at orchestrating political chaos in the country and ousting the AKP government. The allegations have caused Basbug to complain of a psychological campaign to smear the army and warn of a possible confrontation between institutions. Dozens of suspects among them two retired generals accused of being ringleaders are already on trial for alleged membership of the so-called Ergenekon network. Firtina and Ornek had already testified to police in December over supposed links to the anti-government network. The Ergenekon investigation, which began in 2007, was initially hailed as a success in a country where the army has unseated four governments since 1960 and wielded significant political clout.