BAGHDAD — Prime Minister Nouri al Maliki's security services have locked up more than 1,000 members of other political parties over the past several months, detaining many of them in secret locations with no access to legal counsel and using "brutal torture" to extract confessions, his chief political rival has charged.

Ayad Allawi, the secular Shiite Muslim leader of the mainly Sunni Muslim Iraqiya bloc in parliament, who served as prime minister of the first Iraqi government after the Americans toppled Saddam Hussein, has laid out his allegations in written submissions to Iraq's supreme judicial council. Allawi, whose bloc is part of Maliki's coalition government, demanded Wednesday that the prime minister grant the detainees legal counsel and due process.

Some of the confessions obtained under duress were intended to implicate Allawi in a supposed plot to foment violent unrest around the country, Allawi charged in a formal complaint to President Jalal Talabani earlier this month.

"Information has reached us that is beyond doubt regarding the brutal torture of our detainees in an attempt to extract false confessions from them, confessions referring to the general secretary himself," Allawi wrote Talabani. "They are being made to confess that he has ordered armed demonstrators onto the streets to carry out violence."

Interviewed last week in Irbil, the capital of Iraq's autonomous Kurdish region, Allawi said that Iraqiya leaders knew "from our own sources that they are being tortured in prisons and detention camps — one of them had his legs broken — and they've been denied access to their families, access to their lawyers."

He said that 42 members of his political party, the Iraqi National Accord, had been detained: "Their wives, brothers and sisters have been flooding our offices. They want to know what has happened to their relatives, why they have been arrested, and they don't know where they are."

Allawi's allegations were the second major broadside this week against detention practices under Maliki, who's been the prime minister since May 2006.

London's Guardian newspaper reported Monday on an extortion racket involving Iraqi state security officials who systematically arrest people on trumped-up charges, torture them and then extort bribes from their families for their release.

The wave of arrests of Maliki political opponents began in October, around the time it was becoming clear that talks on a continued U.S. presence in Iraq would fail.

The arrests targeted 600 supposed sympathizers of Saddam Hussein's Baath party. But they continued through the end of the year, expanding to members of other political groups.

Maliki's official spokesman, Ali al Dabbagh, didn't respond to an emailed request for comment. His telephones went unanswered Thursday.

Western diplomats scoff at the idea that the arrests were aimed at thwarting a coup.

"This is just paranoia," said one diplomat, who spoke only on the condition of anonymity because of the sensitivity of the subject. "It's fantasy land."

Salim al Juburi, a member of the Iraqiya bloc who heads the Human Rights Committee in parliament, also disputed the government's claim of a conspiracy against it. "That's just an illusion. It's just an excuse to carry out arrests nationwide as the Americans are withdrawing, and was a real attempt to target some politicians," he said.