ISTANBUL (Reuters/AFP) - Twelve senior Turkish military officers were remanded in custody on Wednesday over an alleged plot to topple a government seen by conservative secularists, not least in the army, as pursuing a hidden agenda. Turkeys top military commanders, who have seen the armys role as ultimate guardian of secularism eroded under European Union-backed reforms, held an emergency meeting late on Tuesday and warned in a statement of a serious situation. Prime Minister Tayyip Erdogan, who denies any extremist ambitions, consulted overnight with his deputy and the interior and justice ministers. The tensions were triggered by a dramatic police swoop on Monday that detained around 50 serving and retired officers in an unprecedented operation. The most senior detainees, retired Air Force Commander Ibrahim Firtina and ex-navy chief Ozden Ornek, were being held at police headquarters in Istanbul, while retired admiral Ahmet Feyyaz Ogutcu and 11 other officers were sent to court for questioning, the CNN Turk news channel reported. The seven officers charged overnight included four admirals, two retired and two serving; a retired brigadier-general and two retired colonels, state-run Anatolian news agency said. They have been jailed awaiting trial. Pending a formal indictment, they are accused of belonging to a terrorist group and of attempting to overthrow the government by force. Meanwhile, a Turkish court Wednesday ordered five more suspects to be remanded in custody over an alleged coup plot against the rooted government in 2003, bringing the total number to 12, Anatolia news agency reported. The five suspects, questioned by prosecutors earlier, included a serving soldier and four retired officers, among them an admiral, the report said. Six officers were released from custody on Tuesday after questioning. It was unclear if they would face charges. The army leadership has said previously that probes of a series of alleged coup plots was hurting morale in the ranks. In a characteristically veiled and brief statement on its web site on Tuesday, the General Staff said its top commanders had met to assess the serious situation that has arisen. What do you mean? Are you going to carry out a coup? said a headline in Taraf, a low-circulation pro-government newspaper that has broken several stories of alleged coup plots. The current investigation into the so-called Sledgehammer plan, allegedly drawn up in 2003, was triggered by a report in Taraf last month. The military has said the plan was just a scenario drawn up for an army seminar. Asked about the militarys statement, AK Party Deputy Leader Salih Kapusuz cautioned against meetings or comments that could prejudice the legal process. The government is under some obligation to press on with the investigations to demonstrate to the European Union that it is serious about bringing the military under full civilian control, said Royal Bank of Scotland analyst Timothy Ash. At the same time, further arrests will just further accentuate tensions. Its a difficult balancing act and indeed this might provoke a counter reaction from the secular establishment, Ash said. The countrys chief prosecutor narrowly failed to have Erdogans party banned in 2008 having accused it of anti-secular activities and there is speculation he could try again. Retired military officers are among around 200 people indicted over separate plots by a far-right group known as Ergenekon. Critics say that trial is being used to target political opponents, an accusation the government rejects.