By Syed Shoaib Hasan
BBC News, Islamabad
Police say that the attack was well planned and executed
A former chief of Pakistan's elite military commandos has been killed in a targeted attack near the capital Islamabad, police officials say.
They say that retired General Amir Faisal Alvi and his driver were shot dead on the main highway leading into the city.
Senior military and government officials have been the focus of targeted attacks by militants.
Their deaths have been blamed on their support for the US-led "war on terror".
More than a dozen senior officials have been killed since 2001 in such attacks, while others, including former President Pervez Musharraf and present Prime Minster Yusuf Raza Gillani, have narrowly escaped assassination attempts.
"General Alvi's car was stopped on the highway near Bahria Town by three armed men," Inspector Mohammad Arshad, who is in charge of the investigation, told the BBC.
"The men then sprayed the car in which the general was travelling with bullets. Both he and his driver were killed instantaneously."
Witnesses told police that the killers travelled by motorbike and jeep and fled the scene immediately after carrying out the crime.
"It seems like a well-planned and executed attack," Inspector Arshad said.
Police officials say they are also looking into the possibility that the attack was related to business or personal enmity.
But the top suspects, according to them, are militants from jihadi organisations.
General Alvi retired from the army in 2006 as head of Pakistan's elite commando unit, the Special Services Group (SSG).
The unit has been closely involved in operations against al-Qaeda and the Taleban across Pakistan since 2001.
The unit's main headquarters near the town of Tarbela-Ghazi was the target of a suicide bombing in September 2007, leaving several officers and soldiers dead.