A Turkish court Thursday placed in custody six active and five retired generals as part of a widening probe into the 1997 bloodless coup that toppled the country's first Islamist-led government, the Anatolia news agency reported.

Among the latest senior military officers swept up in the investigation is General Berkay Turgut, the Third Army's chief of staff, it said.

Seventeen senior Turkish military officers, both retired and on active duty, were detained on Wednesday across the country as part of the investigation, accused of "trying to topple the government, or partially or totally impeding its activities."

The investigation concerns the toppling in 1997 of Turkey's first Islamist head of government, Necmettin Erbakan, the political mentor of current Prime Minister Recep Tayyip Erdogan.

On Tuesday, Erdogan voiced uneasiness about the ongoing waves of arrests and called for a swift finalisation of the legal case launched by prosecutors.

"We are seriously disturbed by these arrests. The steps that need to be taken must be taken and (the case) must be finalised," he said.

The 1997 coup is often qualified as "postmodern" as the officers toppled the government without having to use their troops or replacing the civilian administration with the military.

A parade of tanks outside Ankara and an ultimatum addressed to Erbakan at the time were all it took to overthrow his government without violence.

The army, which sees itself as the guarantor of Turkey's secular principles, overthrew three earlier administrations in 1960, 1971 and 1980.

Turkey is currently holding dozens of officers, some of them retired, on suspicion of plotting to oust the latest Islamist-led government which took over in 2002.

The accusations targeting military officers are widely seen as part of efforts by the current Islamist-led government to roll back the military's influence in politics.

According to a poll published on Thursday by liberal daily Radikal, the majority of Turks back the investigation into the 1997 coup, with 67.7 percent of some 1,200 people surveyed saying they believed the probe was "justified and necessary," compared with 27.1% who disagreed, while the remaining 5.2% made no comment.

The Metropoll Institute poll also revealed that only 22.7 percent said they believed trying coup perpetrators was an "act of revenge," while 17.1 percent said they were ready to approve a hitback coup against the Islamic-rooted government.