Islamabad, Jan 13 (Agencies): The police guard who gunned down Punjab Governor Salman Taseer was assigned to protect key personalities, including Pakistan's President, Prime Minister and foreign delegations and has heightened security fears among the country's elite.

Self-confessed killer, Mumtaz Qadri, was detailed on protection duties on as many as 509 occasions in the past three years, including for US delegations who are prime targets, according to a media report today.

The reports attributed to police investigations have also cast suspicions that other elite bodyguards may have been radicalised.

The media reports said this could be alarming as the police force is part of the frontline in the war against terror groups, specially Taliban and al-Qaeda. The report highlights the dangers of radicals infiltrating into the security agencies of unstable and nuclear-armed Pakistan.

US has long worried about the loyalty of Pakistan's security forces, especially the powerful army, given the publicly known links with terror groups fighting in Afghanistan and Kashmir.

Qadri, who surrendered after gunning down Taseer in a market in Islamabad on January 4, has told police he was angered by the Governor's criticism of the blasphemy law.

Investigators are trying to determine whether Qadri had acted alone or was part of a conspiracy.

Qadri was assigned to protect VIPs and VVIPs on 509 occasions despite being declared a "security risk" in 2004 due to his extremist leanings, The News daily quoted a report compiled by intelligence agencies as saying.

The policeman was also part of a team that was used by Military Intelligence and Inter-Services Intelligence to conduct raids against terrorist groups in 2008.

Among the prominent personalities he was assigned to protect were President Asif Ali Zardari, Prime Minister Yousuf Raza Gilani and Supreme Court Chief Justice Iftikhar Chaudhry.

He was also part of the security detail for a foreign delegation on two occasions last year.

Qadri had also been part of the security detail for several politicians, including Interior Minister Rehman Malik, PML-N chief Nawaz Sharif, Punjab Chief Minister Shahbaz Sharif and Chaudhry Nisar Ali Khan, Leader of Opposition in parliament.