Violence increased across Iraq after a lull following the Dec. 15 parliamentary elections, with at least two dozen people including a U.S. soldier killed Monday in shootings and bombings mostly targeting the Shiite-dominated security services.

Officials blamed the surge in violence on terrorist efforts to deepen the political turmoil surrounding the contested vote. Preliminary figures — including some returns released Monday from ballots cast early by expatriate Iraqis and some voters inside Iraq — have given a big lead to the religious Shiite bloc that controls the current interim government.

The violence came as three opposition groups threatened a wave of protests and civil disobedience if fraud charges are not properly investigated. The warning came from the secular Iraqi National List, headed by former Shiite Prime Minister Ayad Allawi, and two Sunni Arab groups.

Iraq's Electoral Commission said Monday that final results for the 275-seat parliament could be released in about a week.

Sunni Arab and secular Shiite factions are demanding that an international body review more than 1,500 complaints, warning they may boycott the new legislature. They also want new elections in some provinces, including Baghdad. The United Nations has rejected an outside review.

"We will resort to peaceful options, including protests, civil disobedience and a boycott of the political process until our demands are met," Hassan Zaidan al-Lahaibi, of the Sunni-dominated Iraqi Front for National Dialogue, said in neighboring Jordan, where representatives of the groups have met in recent days.

Among the complaints are 35 that the election commission considers serious enough to change some local results. But, said Farid Ayar, a commission official, "I don't think there is a reason to cancel the entire elections."

He also said preliminary results from early votes by soldiers, hospital patients and prisoners and overseas Iraqis showed a coalition of Kurdish parties and the main Shiite religious bloc each taking about a third. Those nearly 500,000 votes were not expected to alter overall results significantly.

Preliminary results previously released gave the United Iraqi Alliance, the religious Shiite coalition dominating the current government, a big lead — but one unlikely to allow it to govern without forming a coalition with other groups.

Bahaa al-Araji, a member of the Shiite alliance, said the group was preparing to negotiate with other political blocs and had already met with the Sunni Arab Iraqi Islamic Party.

Al-Araji also said likely candidates for prime minister were current Prime Minister Ibrahim al-Jaafari, who heads the Islamic Dawa party, and Adel Abdul-Mahdi, who belongs to the other main Shiite party, the Supreme Council of the Islamic Revolution in Iraq.

Every time there has been a defining event in Iraq since the fall of Saddam Hussein in 2003, there has been a period of calm. They included the June 28, 2004, transfer of power from the U.S.-led Coalition Provisional Authority, the Jan. 30 elections, and the Oct. 15 constitution referendum.

The recent lull in violence ended Sunday, with the deaths of 18 people.

On Monday, a homicide car bomber slammed into a police patrol in the capital, leaving three dead, officials said, and a homicide motorcycle bomber rammed into a Shiite funeral ceremony, killing at least two, said Maj. Falah Mohamadawi of the Interior Ministry. A mortar then killed two people in a predominantly Shiite neighborhood.

Four other car bombs killed at least two people and gunmen killed five officers at a police checkpoint 30 miles north of Baghdad, officials said.

A U.S. soldier serving with Task Force Baghdad was killed when a rocket-propelled grenade hit his vehicle while on patrol in the capital, the military said. The name of the soldier was withheld pending notification of next of kin.

In Jordan, a lawyer for Saddam and a Jordanian newspaper claimed Monday that the former ruler's half brother rejected a U.S. offer of a ranking Iraqi government position in exchange for testimony against the deposed leader.

The half brother, Barzan Ibrahim, reportedly made the claim Thursday before the Supreme Iraqi Criminal Court which is hearing the cases against him, Saddam and six other co-defendants for the deaths of more than 140 Shiites after a 1982 attempt on Saddam's life in the town of Dujail.

The lawyer spoke to The Associated Press on condition of anonymity because he was not authorized to give details of the closed session.

Saddam's chief Iraqi lawyer, Khalil al-Dulaimi, made the same allegations in Monday's editions of the independent Jordanian daily Al Arab Al Yawm. Dulaimi and U.S. officials were not immediately available for comment Monday, which was a U.S. holiday.

But chief prosecutor Jaafar al-Mousawi denied that there were attempts to cut a deal with Ibrahim during the closed session. "The defense team should respect the profession and should not make false statements," al-Mousawi said. He refused to divulge what happened during the closed session.

In other developments:

• Gunmen raided a house in southern Baghdad, killing three people, police Capt. Qassim Hussein said. Gunmen attacked the house again when police arrived to remove the bodies, wounding two officers, police said.

• A Shiite cleric in the southern city of Najaf and a man in the northern city of Mosul were gunned down. In Baghdad, a civilian driving his children to school and a professor were killed.

• A car bomb targeted the governor of Diyala province, killing a body guard, and gunmen killed a member of Diyala city council.

• Ukrainian President Viktor Yushchenko paid an unannounced visit to his country's troops. His country is pulling out its remaining 867 soldiers this week.

• Susanne Osthoff, a German freed after being held hostage in Iraq for more than three weeks, said in an interview aired Monday that she was treated well by her kidnappers, who told her they do not hurt women or children.