Iraq’s Shiite-dominated government on Monday accused its Sunni vice president of terrorism, plunging the country into its deepest political crisis in years only one day after U.S. troops departed.

As an arrest warrant was issued for Tariq al-Hashimi, three men said on Iraqi television that they had worked as his bodyguards and had carried out bombings and assassinations, killing as many as a half-dozen people.

They said Hashimi knew what they were doing. But many Iraqis questioned whether the allegations rang true.

Neither Hashimi nor his spokesman could be reached for comment. Hashimi was in the semiautonomous region of Kurdistan holding crisis talks with Kurdish leaders.

Iraqi Kurds called for calm, as did U.S. officials in Washington. The charges came despite talks over the weekend among President Jalal Talabani, Prime Minister Nouri al-Maliki, Sunni politicians and U.S. Embassy officials, which appeared to resolve the issue with the creation of a judicial committee to “thoroughly investigate” the terrorism charges.

“We are closely monitoring these reports that an arrest warrant has been issued, in particular, for vice president al-Hashimi,” said Victoria Nuland, a State Department spokeswoman. “We are talking to all of the parties. We’ve expressed our concern regarding these developments. We’re urging all political sides in Iraq to work out their differences peaceably, politically, through dialogue, and certainly in a manner that is consistent with democratic political processes and international standards of rule of law.”

The three men speaking on television offered startling details of what they said were their missions — how an ID was used to get past a checkpoint, how explosives were packed in a black, plastic garbage bag, how they were told precisely the minute that convoys would be passing.

“Tariq al-Hashimi himself always gave me a white envelope containing $3,000, except for one time,” said one of the men, Ahmad Shawqi Aljburi, who claimed that he went on at least six missions that included bombings and assassinations.

Aljburi said that on the last mission, the vice president asked him to provide a daily report diagramming the position of the tanks and checkpoints helping to protect Baghdad’s Green Zone.

“I want to expose the reality of this criminal, al-Hashimi,” Aljburi said. “He destroyed me and my family.” Aljburi accused the vice president of threatening that he and his family would be assassinated if he did not cooperate.

His allegations and those of the two others could not be confirmed.

In recent months, Maliki, a Shiite, has overseen the arrest of hundreds of suspected sympathizers of Saddam Hussein’s Baath Party. His supporters say Maliki is trying to halt acts of terrorism, which have slowed but hardly disappeared in Iraq. On Monday, at least three explosions rocked Baghdad.

Maliki’s critics say he has gone overboard in consolidating his power, particularly now that the U.S. military has left. On Sunday, tensions soared when Maliki asked parliament to hold a no-confidence vote that would enable him to dismiss another top Sunni official, Deputy Prime Minister Saleh al-Mutlak.

Special correspondent Asaad Majeed also contributed to this report.