Gunmen stormed a bus station Wednesday northeast of Baghdad, seizing 24 people and killing all but four of them, authorities said. An Iraqi general said the victims were Shiites, but police said their identities were unclear.

The gunmen arrived in several cars at the bus station in Muqdadiyah, about 60 miles northeast of Baghdad, about 6 a.m., forced the captives into four vehicles they commandeered at the scene and sped away, officials said.

Maj. Gen. Ahmed al-Awad, the commander of the Iraqi army's 5th division, told government television that 20 bodies were later found and the victims were Shiites. He said four people were rescued.

Al-Awad said the attackers separated the Shiites from the Sunnis, then took the Shiites to the nearby village of Ballour. He said nearly 400 Iraqi soldiers raided the village and rescued the four survivors. The other captives had already been moved to the area where the bodies were found, he said. Al-Awad accused local police of failing to intervene.

But police said the identities had not been determined and they didn't know whether all the dead were Shiites. The Muqdadiyah area has a slight Sunni majority and is located in a province where sectarian tension runs high.

The massacre is part of a surge in sectarian violence that began Sunday when Shiite gunmen rampaged through a Baghdad neighborhood killing Sunnis. At least 60 people were killed Tuesday across Iraq, most of them in the Baghdad area.

Prime Minister Nouri al-Maliki warned that sectarian unrest was threatening the future of the nation.

"We all have the last chance to reconcile and agree among each others on avoiding conflict and blood. If we fail, God forbid, I don't know what the fate of Iraq will be," al-Maliki said during an address to parliament.

The United States had hoped that a unity government of Shiites, Sunnis and Kurds could calm sectarian tensions and convince insurgents to lay down their arms so that U.S. and its coalition partners could begin withdrawing troops starting this year.

But more than 1,607 Iraqis have been killed and nearly 2,500 wounded since al-Maliki's unity government took office May 20, according to an Associated Press count.

The top U.S. commander in Iraq said that "terrorists and death squads" are mainly responsible for a surge in sectarian violence in the capital, and he pledged to provide whatever U.S. forces are needed to avert civil war.

Gen. George Casey, at a joint news conference with Defense Secretary Donald H. Rumsfeld, told reporters that al-Qaida is carrying out terrorist killings in the Baghdad area in an attempt to "demonstrate that they are still relevant" after the June 7 killing of their leader in Iraq, Abu Musab al-Zarqawi.

`What we are seeing now as a counter to that is death squads, primarily from Shiite extremist groups that are retaliating against civilians," Casey said. "So you have both sides now attacking civilians, and that is what has caused the recent spike in violence here in Baghdad."

Casey said he was consulting with the Iraqi government on means of counteracting the violence. Asked whether that might include putting more U.S. troops in the Baghdad area, Casey replied, "It may, yes."

Casey and Rumsfeld were meeting later with al-Malaki.

Rumsfeld said earlier Wednesday on an unannounced visit to an air base north of Baghdad the new Iraqi government is not yet ready to decide on security issues that will determine the pace of U.S. troop reductions this year.

Muqdadiyah was the site of a recent Iraqi military operation aimed at stopping an increase in insurgent activity in the mostly rural area, where sectarian tensions run high.

The Iraqi Islamic Party, the largest Sunni political group, complained last week that U.S. and Iraqi troops had surrounded 15 mostly Sunni villages near the city and called on them to allow the entry of food and medicine and to compensate farmers for damage to their crops.

Shiite lawmaker Sheik Jalaluddin al-Saghir told a session of parliament that 50 to 60 Shiites were abducted. But police in Diyala province, where Muqdadiyah is located, later put the figure at 24 and said it included Shiites and Sunnis.

Also Wednesday, a suicide bomber blew himself up in a restaurant in the southeastern mixed Sunni-Shiite neighborhood of New Baghdad, killing eight people and wounding 30, police chief Col. Ahmed Aboud said.

Gunmen on a motorcycles killed a former member of the ousted Baath Party and a taxi driver in separate attacks in Kut, 100 miles southeast of Baghdad.

A parked car bomb also exploded near an Iraqi army base in Haswa, 30 miles south of Baghdad, wounding eight people, while gunmen attacked an army patrol to the north of the capital, wounding four soldiers, police said.

Despite the sectarian bloodshed, fliers were circulated in a predominantly Sunni area north of Baghdad, urging Shiite families not to flee and warning people not to hurt members of the majority sect. The fliers were purported signed by the Mujahedeen Shura Council, an umbrella organization of several Islamic extremist groups, including al-Qaida in Iraq.

In another positive sign, the Iraqi Accordance Front, the largest Sunni bloc in parliament, lifted its legislative boycott and attended Wednesday's session. It thanked the parliament for its help in seeking the release of kidnapped legislator Tayseer al-Mashhadani and called for a new spirit of cooperation.

In his speech to parliament, al-Maliki urged his countrymen to unite behind his administration's efforts to stem the bloodshed.

"It is not only the government that should be responsible. You chose the ministers and the prime ministers. You should not stand up and criticize the government," al-Maliki said in an apparent reference to some lawmakers who criticized the government because of the bad security situation.

He also said that insurgents have plans to take control of Karkh, a large swath of western Baghdad that extends north.

"They have intentions to occupy Karkh, but be sure that Iraqi forces are capable of repulsing them and have started striking them," he said.

"The government cannot protect every child and every woman," al-Maliki said. "Military forces will deter anyone who tries to occupy any area."

He added that the government will work on cleaning up the security and armed forces in order "to make them far from political groups and sectarianism."