An Iraqi court heard on Tuesday testimony from witnesses claiming Vice President Tareq al-Hashemi masterminded killings of his opponents, charges he has dismissed as politically-motivated.

The Central Criminal Court of Iraq opened the case after a two-week delay over a venue dispute, and also heard testimony from relatives of three victims whose deaths Hashemi is accused of orchestrating.

Hashemi, one of the country's top Sunni Arab officials, was accused in December of running a death squad and, along with his staff and bodyguards, faces around 150 charges.

The vice president, last known to be in Turkey, is the subject of an Interpol red notice calling for his arrest but says he fears for his life in Baghdad, and is being tried in absentia.

Tuesday's hearing was tackling the murders of two security officials and a lawyer.

Witnesses gave testimony accusing Hashemi of masterminding the killings before reporters were led out of the room.

"He asked me to plant a car bomb near Buratha mosque, and I carried out the operation," Ahmed Shawqi, identified by court officials as one of Hashemi's bodyguards, told the court.

"The orders for the operations either came from him personally, or from his brother-in-law Ahmed Qahtan."

"I was the leader of the operation that targeted Ghalib al-Assadi because he was causing problems for Tareq al-Hashemi, and he wanted to eliminate him," he claimed, referring to one of the security officials killed.

Shawqi was questioned as a witness, but is among several dozen of Hashemi's bodyguards who along with the vice president face a total of around 150 charges according to a judicial spokesman.

The next hearing in the trial was set for May 20.

The charges against Hashemi were first levelled in December after US troops completed their withdrawal, sparking a political crisis that saw his bloc boycott cabinet and parliament, accusing Shiite Prime Minister Nuri al-Maliki of monopolising power.

Hashemi and his political allies have slammed the charges against them as targeting their Sunni Arab-backed Iraqiya bloc, which won the most seats in March 2010 parliamentary elections but was outmanoeuvered for the premiership by Maliki's alliance.

After the initial charges were filed, the vice president fled to the autonomous Kurdistan region in northern Iraq, whose authorities declined to hand him over to the central government.

They then allowed him to leave on a tour of the region that has taken him to Qatar, Saudi Arabia and now Turkey. Ankara has said it will not extradite him to Iraq.