A Turkish court has charged seven senior military officers with plotting to overthrow the government. Four are admirals and one is a general.
They were among about 50 senior military figures, some retired, who were detained on Monday.
The BBC reports the scale of the operation against the military was unprecedented and increased the tension between the government and the armed forces.
The army regards itself as the guardian of a secular Turkish state. It has overthrown or forced the resignation of four governments since 1960 - the last time in 1997.
Top generals and admirals met at short notice on Tuesday to evaluate what was described as a "serious situation".
Dozens of current or former members of the military have been arrested in the past few years on similar accusations.
Reports of the plot first surfaced in a liberal newspaper, Taraf, which said it had discovered documents detailing plans to bomb two Istanbul mosques and provoke Greece into shooting down a Turkish plane over the Aegean Sea.
The army has said the plans had been discussed as part of a planning exercise at a military seminar.