BAGHDAD (AP) ― Iraq’s Shiite-led government issued an arrest warrant Monday for the Sunni vice president, accusing him of running a hit squad that assassinated government and security officials ― extraordinary charges a day after the last U.S. troops left the country.

The vice president, Tariq al-Hashemi, left Baghdad on Sunday for the semiautonomous Iraqi region of Kurdistan, presumably hoping that Kurdish authorities would not turn him in. Investigative judges banned him the same day from traveling outside of Iraq.

The move against the country’s highest-ranking Sunni official marked a sharp escalation in sectarian tensions, raising fears of a resurgence of large-scale bloodshed. Although many Iraqis welcomed the American withdrawal, ending the nine-year U.S. war, there are also considerable fears here that violence will worsen.

“Iraq is slipping into its worst nightmares now, and Iraqi people will pay a high price because of the struggle among political blocs after the pullout of U.S. troops,” said Baghdad-based political analyst Kadhum al-Muqdadi, a Shiite.

White House spokesman Jay Carney said the Obama administration had expressed its concerns to all of the parties involved regarding the issuing of the warrant.

“We are urging all sides to work to resolve differences peacefully and through dialogue in a manner consistent with the rule of law and the democratic political process,” Carney said.

Sunnis suspected the charges against al-Hashemi were politically motivated. Al-Hashemi is an old rival of Prime Minister Nouri al-Maliki, and the arrest order came two days after the main Sunni-backed political bloc, Iraqiya, suspended its participation in parliament because al-Maliki refused to give up control over key posts.

Al-Maliki, a Shiite, has made a series of moves in recent months to consolidate his hold on power. Hundreds of former members of Saddam Hussein’s Baath Party have been rounded up, allegedly as security threats, although no proof has been given. In Tikrit, Saddam’s hometown, arrests have become so commonplace that whenever a police car shows up, young men flee from the street.

State-run television aired what it characterized as confessions by men said to be working as bodyguards for al-Hashemi. The men said they killed officials working in Health and Foreign Ministries as well as Baghdad police officers, and that they received $3,000 from al-Hashemi for each attack.

“An arrest warrant has been issued against Vice President al-Hashemi under the terrorism law and five judges have signed this warrant,” said Interior Ministry spokesman Adil Daham said as he waved a copy of the order.

Al-Hashemi, one of two vice presidents in Iraq, could not be reached for comment.

Since the 2003 U.S.-led invasion that toppled Saddam and his Sunni-dominated Baath party regime, the Sunni minority has constantly complained of attempts by the Shiite majority to sideline them.

At first the Sunnis waged an insurgency against the Americans, then became U.S. allies against al-Qaida, but relations with the Shiite-led national government are still frosty.

Everyday relations between Sunnis and Shiites are much better than they were at the height of the insurgency, when neighbors turned on neighbors and whole sections of Baghdad were expunged of one Muslim sect or the other. Sunnis and Shiites can travel throughout the country without fear of being shot at a checkpoint by a militia.

Iraq is now far quieter than at the height of the war but with an uneasy peace achieved through intimidation and bloodshed. The number of Iraqi neighborhoods in which members of the two Muslim sects live side by side and intermarry has dwindled.

The forced segregation, fueled by extremists from both communities, has fundamentally changed the character of the country. And it raises questions about whether the Iraqis can heal the wounds of the sectarian massacres now that the American soldiers have left.

Toward the end of the U.S. occupation, many Sunnis came to feel that the American military was treating them fairly, or at least more fairly than the Shiite-led government. They fear that the U.S. departure now means the loss of a protector.

The parliament boycott by Iraqiya, headed by Ayad Allawi, was in response to the government’s failure to share more powers, particularly the posts that control security forces, said Sunni lawmaker Hamid al-Mutlaq, a member of the bloc.

Iraqiya narrowly won the most seats in last year’s parliamentary election, but Allawi was outmaneuvered by al-Maliki, who kept the premier’s post after cobbling together key support from other Shiite parties.

For more than a year now, al-Maliki has effectively controlled the Interior and Defense Ministries, which oversee the police and military, while conflicts between Sunni and Shiite politicians have delayed the appointment of permanent ministers.

Al-Mutlaq warned that Iraqiya could take a further step if its demands are not met ― pulling its seven ministers out of al-Maliki’s coalition government.

The Sunnis feel they are being penalized simply for being Sunnis like Saddam. The Shiites feel that after more than three decades of suppression by the totalitarian Baathist creed, they need to be especially vigilant in stamping it out. Al-Maliki, the Shiite prime minister, is himself a former dissident who spent 24 years in exile and was sentenced to death by Saddam.