ISLAMABAD: A UN commission appointed to investigate the assassination of Pakistan's former prime minister Benazir Bhutto began work on Wednesday, a spokesman said.

The panel, which has a six-month mandate, is being led by the Chilean ambassador to the United Nations, Heraldo Munoz, and includes an Indonesian ex-attorney general and an Irish former police official.

Bhutto, the first woman to become prime minister of a Muslim country, was killed on December 27, 2007 in a gun and suicide attack after addressing an election rally in Rawalpindi, a garrison city near the capital Islamabad.

"The six-month mandate of the Benazir Bhutto commission of inquiry has begun today. The commission is expected to visit Pakistan but the dates are not determined yet," Hiro Ueki, a UN spokesman in Pakistan, told AFP.

The United Nations has said the panel will inquire into the facts and circumstances of the assassination, but have made clear it will be up to Pakistan to determine "the criminal responsibility of the perpetrators."