Baghdad, Iraq ? Suicide bombers and gunmen killed nearly two dozen people across Iraq on Sunday, shattering the relative quiet since the parliament election, as President Bush said the vote had strengthened a new ally and warned against a U.S. pullout.

Hours before Bush spoke, Vice President Dick Cheney made a surprise visit to Iraq and said the election’s strong turnout had brought Iraq closer to taking control of its own security. But Cheney also cautioned against a rapid U.S. withdrawal.

Bush said last week’s voting would not end violence in Iraq but “means that America has an ally of growing strength in the fight against terror.” He warned a U.S. troop pullout would “signal to the world that America cannot be trusted to keep its word.”

“We would hand Iraq over to enemies who have pledged to attack us, and the global terrorist movement would be emboldened and more dangerous than ever before,” he said.

Germany’s government, meanwhile, said kidnappers had freed a German woman who was taken hostage in northern Iraq more than three weeks ago. Susanne Osthoff, a 43-year-old aid worker and archaeologist, was reported in good condition at the German Embassy in Baghdad.

A series of attacks that began late Saturday ended three days of near calm that began with Thursday’s elections for the first full-term parliament since Saddam Hussein was toppled.

U.S. Vice President Dick Cheney talks with U.S. soldiers after having lunch at the Taji Air Base and touring the 9th Mechanized Infantry Division of the Iraqi Army. Cheney also met with Iraqi leaders and the U.S. Military Command to discuss security and the latest elections during his surprise visit.

Most of the people killed in the new violence, which included two suicide bombings, were police officers. The bloodshed came after authorities eased security measures ordered for the elections and traffic returned to normal on the first full working day since the vote.

Top-secret visit

Cheney’s visit was so secret that Iraqi Prime Minister Ibrahim al-Jaafari was surprised when he met him at the U.S. ambassador’s residence in the heavily fortified Green Zone.

The one-day trip focused on the successful legislative election and the strong turnout in all of Iraq’s religious and ethnic communities.

“The participation levels all across the country were remarkable,” Cheney told reporters after an hourlong briefing from U.S. military commanders. “And that’s exactly what needs to happen as you build a political structure in a self-governing Iraq that can unify the various segments of the population and ultimately take over responsibility for their own security.”

The big turnout – particularly among Sunni Arabs who boycotted the election of an interim legislature last Jan. 30 – has raised expectations that increased political participation may undermine the Sunni-led insurgency and allow U.S. troops to begin pulling out next year.

But Cheney stressed the Bush administration did not plan a rapid withdrawal.

“You’ve heard some prominent voices advocating a sudden withdrawal of our forces from Iraq,” he told hundreds of troops. “Some have suggested that the war is not winnable, and a few seem almost eager to conclude the struggle is already over. But they are wrong. The only way to lose this fight is to quit, and that is not an option.”

Al-Jaafari told Cheney that he estimated a record 70 percent of Iraq’s 15 million registered voters went to the polls.

“We have been able to move forward several decades. The year 2005 is the most important in the history of Iraq in terms of productivity, of the establishment of the democratic process, the establishment of the constitution, the establishment of the Iraqi parliament,” he said.

Iraqi authorities were still tallying the ballots that will determine the allocation of the parliament’s 275 seats for four-year terms. Results likely won’t be known for days.

Hostage now free

In Berlin, German Foreign Minister Frank-Walter Steinmeier offered no details in announcing the release of aid worker Susanne Osthoff, saying only that she was free and now at his country’s embassy.

Osthoff, 43, and her Iraqi driver disappeared Nov. 25 in northern Iraq. Days later, the two were shown in a videotape blindfolded and sitting on a floor, with militants – one armed with a rocket-propelled grenade – standing beside them.

The captors threatened to kill the hostages unless Germany stopped dealing with the Iraqi government. German Chancellor Angela Merkel responded that her country would not be “blackmailed.”

While Germany strongly opposed the U.S.-led invasion of Iraq and refused to send troops here, it does train Iraqi soldiers and police outside this country.