ANKARA, Turkey — Police detained three retired generals and dozens of others in raids across Turkey on Wednesday, as they broadened their investigation into an alleged plot by secularists to overthrow Turkey's Islamic-rooted government.

In was the 10th time in more than a year that police have targeted prominent secularists, who are accused of trying to destabilize Turkey with a string of attacks ahead of a coup that was never carried out.

Eighty-six people — including former army officers, journalists, a former university dean and a lawyer — already are on trial in the case. They have pleaded innocent and accuse Prime Minister Recep Tayyip Erdogan's government of attempting to silence secular critics.

The case is widely perceived as being part of a power struggle between Turkey's secular establishment, including parts of the military, and the democratically elected and religiously conservative government. It also has raised concerns about political instability in Turkey, a country that has endured the ouster of four governments by the military since 1960.

Turkey's state-run Anatolia news agency said nearly 40 people were detained during Wednesday's police raids, and local media said the suspects were taken into custody at homes and offices in about a dozen cities or towns. Police confirmed the raids, but provided few details.

Deniz Baykal, the leader of the country's main opposition party, accused Erdogan's government of conducting a "political vendetta" against anyone in opposition to the government.

"The detentions have turned into a revenge campaign," Baykal said. "These are respected people who defended the secular republic."

Justice Minister Mehmet Ali Sahin rejected Baykal's allegations, telling reporters that the arrests were "purely legal, not political."

Anatolia said police detained three former generals, including Tuncer Kilinc, who once headed Turkey's National Security Council.

The other secularists detained in Wednesday's raids also included two military colonels — Mustafa Donmez and one identified only by the initials C.K. — according to Anatolia news agency and other news reports.

Police also confiscated five guns and 22 hand grenades at the home of a serving military officer in western Izmit city, near Istanbul, Anatolia reported.

AP correspondent Suzan Fraser contributed to this report from Ankara.