Amid increased security, Shiite Muslims in Iraq (search) marked their holiest day of the year on Saturday, one day after a wave of bloody attacks killed 36 people in the deadliest violence to hit this insurgent-wracked nation since the Jan. 30 national elections.

As hundreds of thousands of people converged on holy Shiite sites in the south, a car bomb exploded outside an Iraqi National Guard (search) base in Baqouba, 35 miles northeast of Baghdad, killing one Iraqi guardsman and wounding another, police Col. Muthafar Shahab said. The suicide bomber also died in the blast, he said.

Another car bomb exploded at an Iraqi army checkpoint in Latifiya, 20 miles south of the capital, killing two Iraqi soldiers, an army officer said on condition of anonymity.

In southern Baghdad, gunmen holed up in a building opened fire on a funeral procession in which mourners were carrying coffins of some of the dead killed Friday in a bombing at the capital's al-Khadimain mosque, witnesses said.

Iraqi National Guard troops guarding the procession foiled the attack, however, returning fire and capturing one of the assailants, said Sgt. Ali Hussein. No casualties were reported.

Massive twin blasts in Karbala and Baghdad killed at least 181 people on Ashoura — the Shiite holy day — last year. Authorities, bracing for more violence, have stepped up security this year, prohibiting vehicle traffic — even motorcycles, bikes and pushcarts — into the holy city of Karbala in a bid to avert bomb attacks.

Hundreds of thousands people thronged the streets of Karbala and other holy Shiite cities to mark Ashoura, which commemorates the death of the Shiite saint Imam Hussein, a grandson of the prophet Muhammad. Hussein was killed in a power struggle in the seventh century and is buried in a gold-domed shrine in Karbala.

There were no immediate claims of responsibility for Friday's blasts — three of them suicide attacks — in Baghdad and Iskandariyah, south of the capital. But Shiites blamed radical Sunni Muslim insurgents, who have staged car bombs, shootings and kidnappings to try to destabilize Iraq's reconstruction.

"Those infidel Wahhabis, those Usama bin Laden (search) followers, they did this because they hate Shiites," said Sari Abdullah, a worshipper at Baghdad's al-Khadimain mosque who was injured by shrapnel from the explosion. "They are afraid of us. They are not Muslims. They are infidels."

Friday's attacks on Shiites began with two suicide bombings outside mosques in predominantly Shiite neighborhoods of Baghdad.

The first explosion at the al-Khadimain mosque killed 15, while the second, at al-Bayaa, took 10 lives, an official at Baghdad's al-Yarmouk Hospital said on condition of anonymity. The al-Khadimain bombing occurred just outside the entrance to the mosque as people were still inside praying. The al-Bayaa attack also took place outside the mosque, as prayers were about to end.

Another explosion hit a Shiite religious procession, killing two and injuring five, according to Iraqi police Lt. Waed Hussein. A fourth attack, involving a suicide bomber, struck an Iraqi police and National Guard checkpoint in a Sunni neighborhood, killing at least one policeman.

Later Friday, a car bomb exploded outside a Shiite mosque in Iskandariyah — 30 miles south of the capital — where hundreds had gathered, killing eight people and wounding 10, doctors said.

Mouwaffaq al-Rubaie, the national security adviser for the interim government, accused Jordanian-born terror suspect Abu Musab al-Zarqawi and former Baath party members of trying to provoke a sectarian civil war.

"It's a paradoxical idea when they claim that they are fighting the infidels and at the same time, they kill Muslims during Friday prayers," he said.

He said Shiites, who make up 60 percent of the population, would not call for retaliation against the minority Sunnis who were favored by Saddam Hussein's regime.

"I am happy and proud of the people's reactions," al-Rubaie said. "Those who lost their sons and relatives didn't call for retaliation against Sunnis, which reflects their awareness and understanding of what is going on."

Walid al-Hilly, a leading figure of the Shiite-led Dawa Party, said the attacks would not stop the Shiites from trying to cooperate with Sunnis and other minorities in a new government.

"They kill unarmed men, women and children who want to glorify the ceremonies of Ashoura. These terrorist actions will not intimidate us nor make us change the way that we choose freedom," he told Al-Jazeera television. "We chose the path of brotherhood, cooperation and unity between Sunnis, Shiites, Kurds, Shabak, Turkomen and Christians and all other sects."

The attacks made Friday the deadliest day since last month's elections for a new national assembly. The Shiite ticket, the United Iraqi Alliance, won 48 percent of the vote in Iraq's first democratic balloting, while Sunnis mostly did not vote.

In a reminder of the dangers facing American troops here, a U.S. soldier was killed Friday on patrol in northern Iraq and a second was killed in the south, the military said. Three other American soldiers were killed in separate attacks in the country's north on Wednesday and Thursday.