Men inspect the destruction at a liquor warehouse that was targeted by a car bomb explosion in central Baghdad. (AHMAD AL-RUBAYE/AFP/GETTY IMAGES)

Terrorist attacks, including a bombing Tuesday that killed two dozen people, are intensifying across Iraq as the country’s political blocs step up discussions about whether the coalition government will ask the United States to keep some troops here past the end of the year.

In separate incidents Tuesday that both Sunni and Shiite extremist groups are suspected of carrying out, twin car bombs detonated at a heavily fortified town council building in Diwaniyah province, an explosion tore through a cafe in southern Iraq, and rockets and car bombs shook different sections of Baghdad.

The violence comes as U.S. officials continue to look for signs that the Iraqi government will reach consensus on whether it wants any American troops to remain past their scheduled Dec. 31 withdrawal date.

On Monday, Iraqi President Jalal Talabani held a meeting of top-ranking Iraqi government leaders, including Prime Minister Nouri al-Maliki, to try to jump-start discussions on a continued U.S. presence.

But with broad divisions remaining over such a move, Iraqi and U.S. officials think it could be weeks, if not months, before any formal request would be made to the White House.

Complicating the discussion, radical Shiite cleric Moqtada al-Sadr said through a spokesman this week that his Sadrist political bloc will withdraw from Maliki’s governing coalition if any U.S. troops remain.

“We think that the extension of the U.S. in Iraqi is a red line,” Salah Alubadi said. “If this happens, we will present a lawsuit to the federal court.”

Other politicians are skeptical of Sadr’s influence on the process, and there are signs that continued uncertainty about the readiness of police and military forces could prompt Maliki and his rival, Ayad Allawi — a former prime minister who heads the Iraqiya political bloc — to reach an agreement for at least a few thousand troops to remain into 2012. Allawi was traveling and did not attend Talabani’s meeting.

Mayson al-Damaluji, the spokeswoman for Iraqiya, said even some Sadrists who attended Talabani’s meeting expressed concern about Iraq’s long-term security.

“We have national interests like the water sources and the oil fields, and we must ask ourselves: Are we able to protect it?” Damaluji said. “We made that question [Monday] to the prime minister and are waiting for his answer.”

Security concerns come amid mounting frustration about disruption caused by terrorist attacks.

On Tuesday, 25 police officers and Army officials were killed in Diwaniyah, a predominantly Shiite area in south-central Iraq, when two cars were detonated moments apart at a compound that includes both the governor’s home and the provincial government headquarters. It was the second attack in less than a week on a heavily fortified provincial council building.

In both incidents, local officials said they suspect Sunni-dominated al-Qaeda in Iraq or one its affiliates was responsible. But U.S. and Iraqi officials also fear that Shiite extremist groups are stepping up their attacks to destabilize the government amid the talks about a continued U.S. presence.

Also Tuesday, in Musayab in Southern Iraq’s Babel province, at least two people were killed and eight wounded when an explosion tore though a cafe, Iraqi security officials said.

In southern Baghdad, a bomb detonated in a minibus, often used here to transport commuters and shoppers. At least one person was killed and three were injured. An Iraqi army convoy also struck a roadside bomb on Baghdad’s Palestine Street, killing one soldier and injuring three others and two civilians walking nearby, Iraqi security officials said.

Several mortars were fired Tuesday afternoon onto a joint Iraqi-U.S. base in eastern Baghdad, probably from the Shiite-dominated Sadr City neighborhood. It was unclear whether any U.S. troops were injured, but Iraqi security officials said civilians were wounded in a nearby neighborhood when three mortars landed short of the base.

“It is necessary to revise the current security plans,” Tariq al-Hashimi, Iraq’s vice president, said Tuesday in calling for the formation of an committee to examine the problem.

But there were signs Tuesday that Iraqi security officials are making some progress in containing the violence.

In Baghdad, officials arrested four men on allegations that they made 27 assassination attempts on government or security officials in recent months.

Security officials in Ramadi in Anbar province in western Iraq also intercepted two cars packed with explosives Tuesday. The drivers of the vehicles, who were arrested, were apparently attempting to bomb the headquarters of the Anbar Provincial Council, security officials said.

Special correspondents Aziz Alwan and Asaad Majeed in Baghdad and Sa’ad Sarhan in Najaf and Hassan al-Shimmari in Diyala contributed to this report.