BAGHDAD, 25 January 2005 — A suicide bomber blew up a carload of explosives outside interim Prime Minister Iyad Allawi’s party headquarters yesterday, wounding at least 10 people in the latest blast claimed by Al-Qaeda in Iraq.

Officials announced the arrest of a top Al-Qaeda lieutenant of Abu Mussab Al-Zarqawi, blamed for most of the car bombings in Baghdad — including the bloody 2003 assault on the UN headquarters.

Fighting raged yesterday near Baghdad’s international airport, preventing two Jordanian passenger planes from landing, and sporadic explosions rumbled through the capital into the night. The cancellations left many passengers stranded, including eight Chinese construction workers who were freed by their Iraqi kidnappers this weekend.

The latest violence raised fresh fears about the safety of voters in Sunday’s national elections, which Sunni insurgents have threatened to sabotage. Leaders of a Shiite faction expected to fare best at the polls said they had no intention of establishing an Iranian-style clerical state. The suicide bomber struck at a police checkpoint protecting the offices of Allawi’s party, the Iraqi National Accord. Police said the guards opened fire moments before the blast, which triggered a thunderous explosion that reverberated throughout the city center.

Eight policemen and two civilians were injured, according to Dr. Mudhar Abdul-Hussein of Yarmouk Hospital. It was the second suicide attack against Allawi’s party office this month. In a web posting, Al-Qaeda’s affiliate in Iraq said the attack was carried out by “one of the young lions in the suicide regiment” against the “agent of the Jews and the Christians.”

The blast occurred one day after an audiotape appeared on the web, purportedly from Zarqawi, in which the speaker declared “fierce war” on democracy. He said anyone who takes part in next weekend’s elections would be considered “an infidel.” “We have declared a fierce war on this evil principle of democracy and those who follow this wrong ideology,” the speaker said. “Anyone who tries to help set up this system is part of it.”

The authenticity of the tape could not immediately be verified, but Zarqawi’s group has been behind many of the car bombings, beheadings, assassinations and other attacks in Iraq. The United States has offered a $25 million reward for Zarqawi’s capture or death — the same amount as for Al-Qaeda leader Osama Bin Laden.

In a statement yesterday, the government said it had arrested a top Zarqawi lieutenant during a raid in Baghdad on Jan. 15. The statement said Sami Mohammed Ali Said Al-Jaaf, also known as Abu Omar Al-Kurdi, was responsible for 32 car bombings and was linked to the August 2003 bombing of UN headquarters in Baghdad that killed the top UN envoy in Iraq, Sergio Vieira de Mello, and 21 others.

Al-Jaaf “confessed to building approximately 75 percent of the car bombs used in attacks in Baghdad” since the Iraq war began, Allawi’s spokesman Thaer Al-Naqib said in the statement.

The UN attack was “planned and directed by two others affiliated” with Al-Jaaf, the statement said. It said Al-Jaaf built the car bomb used to attack a mosque in Najaf that killed more than 85 people, including Ayatollah Mohammed Baqir Al-Hakim, in August 2003. He also assembled the car bomb used to assassinate Ezzidine Salim, president of the since disbanded Iraqi Governing Council in May, the statement said.

Two other militants linked to Zarqawi’s terror group also have been arrested, authorities said. They included the chief of Zarqawi’s propaganda operations and one of the group’s weapons suppliers, the statement said.