The relentless violence intensified Wednesday evening, with at least 41 people killed by bomb attacks in the capital, an Interior Ministry official said. Another 174 people were wounded, the official said. The vast majority of the victims were Shiite pilgrims.

In the latest attacks, which occurred despite heightened security, a roadside bomb detonated in western Baghdad Wednesday evening, killing at least six pilgrims and wounding 30 others.

Another bombing, in central Baghdad's Haifa street, wounded nine pilgrims on Wednesday evening.

A suicide bomber struck at pilgrims in northern Baghdad's predominantly Sunni Adhamiya district as they were walking toward neighboring Kadhimiya, where hundreds of thousands of pilgrims had gathered to mark the anniversary of the martyrdom of Imam Musa al-Kadhim. Twenty-eight were killed and 81 were wounded, the official said.

Two roadside bombs left at least five pilgrims dead and 36 wounded in eastern Baghdad's mostly Shiite districts of New Baghdad and al-Fudhailiya, the official said.

A roadside bomb targeting pilgrims exploded in al-Bayaa, in southeastern Baghdad, wounding at least six. In central Baghdad, another five pilgrims were wounded in a roadside bomb blast.

Earlier Wednesday, soldiers at an army checkpoint west of Baghdad fired upon a vehicle driven by a suicide attacker when he refused to stop, Interior Ministry officials told CNN. The vehicle exploded, leaving one civilian dead and four Iraqi army soldiers and police wounded. It was unclear whether the attacker detonated the bomb or if shots fired at the vehicle triggered the explosion.

In another incident, a roadside bomb targeting an army patrol exploded in the Al-Jamia neighborhood of western Baghdad, wounding three soldiers.

A bomb attached to a police officer's car went off Wednesday as he was driving in the Dora neighborhood in southern Baghdad. The officer was killed, officials said.

The attacks came a day after bombings left at least nine dead and 43 wounded. Pilgrims have been targeted since Friday.

The capital is under tight security for the pilgrimage, with many roads blocked and a ban on motorcycles and bicycles in place.

Security measures include: Vehicles to transport pilgrims; thousands of deployed troops; security cameras in and around the shrine; aerial surveillance; and 500 personnel to combat the threat of female suicide bombers.

The Kadhimiya shrine is one of the holiest to Shiite Muslims around the world. The imam died more than 1,200 years ago.