TWO CAR BOMBS exploded this evening in the Iraqi capital and killed at least 16 people, authorities said. At least one appeared to target Shiite pilgrims, sinking the country deeper into a new wave of sectarian violence.

The second car bomb struck near a police vehicle in the Shiite neighborhood of al-Shaab, killing three policemen and four other people, police and hospital officials said. Earlier in the day, a roadside bomb killed two Shiite pilgrims in a Baghdad suburb. The attacks were the latest in a wave of violence primarily targeting Shiites that has killed more than 90 people in less than a week.

The leaders of Iraq’s rival sects have been locked in a standoff since last month, when authorities in the Shiite-dominated government called for Sunni Vice President Tariq al-Hashemi’s arrest on terrorism charges just as the last American troops were withdrawing from the country. Al-Hashemi is Iraq’s highest ranking Sunni politician.

The political crisis pits the leaders of the country’s mostly ethnic- and sectarian-based party blocs against each other. Iraq’s Sunni minority dominated the government under the dictatorship of Saddam Hussein, but since he was overthrown, Shiites have controlled government.

Many fear the crisis will push Iraq toward a renewal of the large-scale sectarian warfare that pushed the country to the brink of civil war in 2006-7.

Al-Hashemi fled several weeks ago to semiautonomous Kurdish region in northern Iraq, where he is effectively out of reach of state security forces. He said Monday that the demand by Shiite Prime Minister Nouri al-Maliki that he be turned over for trial in Baghdad is hurting efforts to end the crisis.

Monday’s attacks began with a roadside bomb blast in the morning in the Baghdad suburb of Awairij. Officials said that explosion killed two Shiite pilgrims walking to the holy Shiite city of Karbala, 50 miles (80 kilometres) south of Baghdad, to commemorate Arbaeen, the end of 40 days of mourning following the anniversary of the death of Imam Hussein, a revered Shiite figure.

The two car bombs struck in the evening. One went off in the western neighbourhood of al-Muwasalat, which is largely Sunni. However, authorities say that blast, which killed nine, appeared to have targeted Shiite pilgrims also making their way to Karbala.

Officials spoke on condition of anonymity because they were not authorised to release the information to the media.