BAGHDAD, Iraq - A car bomb exploded outside a Shiite mosque in Baghdad today where worshippers were celebrating a major Muslim holiday, killing at least 14 people and wounding 40, police and hospital officials said, the country's latest violence in the lead-up to this month's elections.

The car blew up outside the al-Taf mosque in the capital's southwest, where Shiites were celebrating one of Islam's most important holidays, Eid al-Adha, or Feast of Sacrifice. The feast coincides with the yearly pilgrimage to Mecca in Saudi Arabia.

Attacks on Shiites have increased in the run-up to Iraq's Jan. 30 parliamentary and provincial elections. Today's blast was the second outside a Shiite mosque in the capital this week and it came a day after a chief terror leader in Iraq berated Shiites in an Internet audio recording that appeared aimed at sowing division in the country.

Iraq's Shiites - a community that was oppressed for decades - strongly supports the vote, believing it will propel them to a position of influence equal to their standing as the country's majority group. They make up about 60 percent of the Iraq's 26 million people.

But militants among the Sunni Arab minority - which lost privilege when their patron Saddam Hussein was toppled - have vowed to stop the vote. Some Sunni clerics and politicians have called for a boycott of the vote, saying violence in Sunni areas will keep people from the polls and skew the outcome of the balloting against them.

In a new Internet audio recording purportedly from Iraq's most feared terror leader, Jordanian-born Abu Musab al-Zarqawi, the speaker denounced Iraqi Shiites for fighting alongside U.S. troops.

Al-Zarqawi, the leader of Iraq's al-Qaida affiliate, ridiculed Iraq's most prominent Shiite cleric, Grand Ayatollah Ali al-Sistani, and berated Shiites for fighting alongside American troops against their Sunni countrymen in Fallujah in November.

The authenticity of the tape could not be verified.

Today's car bomb exploded as worshippers were leaving the building, a witness said. The blast left several cars in flames and showered the area with charred debris.

At al-Yarmouk Hospital, dozens of weeping men and women franticly searched for news about loved ones feared caught up in the bombing.

A distraught man sat beside his dead 14-year-old son, covered with a sheet, and cried out, "I had breakfast with him this morning. I told him, 'Let's go to your grandfather,' but he insisted on going for prayers first."

A woman dressed in a black cloak, or abaya, fainted as she identified the body of her son in the hospital's morgue. She was carried away by relatives.

In the 90-minute message posted on the Web Thursday, al-Zarqawi called on his followers to show patience and prepare for a long struggle against the Americans, promising that "ferocious wars ... take their time" but that victory was assured.

Al-Zarqawi's al-Qaida in Iraq group was responsible for kidnapping and beheading several foreigners, including Americans, before the fall of their Fallujah base. The United States has offered a $25 million reward for al-Zarqawi's capture or death - the same amount as for Osama bin Laden.

A U.S. soldier was killed today during a pre-dawn raid north of Baghdad, the military said.

The soldier from Army's 1st Infantry Division, whose name was withheld pending notification of his family, was killed in an operation to kill or capture members of an insurgent bomb-making cell in the town of Ad Duluiyah, the military said in a statement.