Agencies
Islamabad, Sep 3: Two bullets from an unidentified gunman hit Pakistan PM Gilani's car as he was travelling just outside the capital, Islamabad on Wedesday, September 3 afternoon.
Gilani's government is grappling with a growing threat from militants in the country.
In December former Prime Minister Benazir Bhutto was killed at an election rally in Rawalpindi.
Major lapse
Gilani was travelling in a bullet-proof car in a convoy between Islamabad and the nearby city of Rawalpindi after landing on an internal flight at Islamabad airport.
"I can confirm the prime minister's convoy was fired upon while returning from Chaklala airport," told his press secretary Zahid Bashir.
"The prime minster was coming back from Lahore. The firing took place on the Islamabad highway. At this point, we believe the firing was from a small hill on the roadside."
Television pictures indicated that the bullets hit the windows of the driver's door.
Officials say another car in the convoy was also hit by several bullets. There are no reports of injuries.
However the interior ministry gave a different account of the incident, saying that Gilani was not in the car at the time of the attack, the AFP news agency reports, because the the motorcade had been on its way to the airport to pick up Gilani.
The BBC's Syed Shoaib Hasan in Islamabad says the incident represents a major lapse in security.
Gilani had been in Lahore to canvass support for Asif Zardari, Ms Bhutto's widower, ahead of presidential elections on Saturday.
Ms Bhutto had been favourite to win Pakistan's general elections and become prime minister for a third time before she was killed on 27 December. The elections were subsequently postponed until February.
Her Pakistan People's Party (PPP) emerged as the winners and formed a coalition with the PML-N party of another former Prime Minister, Nawaz Sharif. Mr Gilani, himself a senior PPP member, became prime minister
The coalition broke up amid political acrimony late last month.
Confident
One of the biggest challenges facing Mr Gilani's government comes from Islamist militants who control large areas along the border with Afghanistan.
The army has been engaged in a major operation in recent weeks in the district of Bajaur which is estimated to have displaced up to 300,000 local people.
This week the government said the Bajaur operation would be suspended during Ramadan.
Last year militants grew increasingly confident and carried out a series of attacks in Islamabad and Rawalpindi, the country's main garrison town.
And last month a double suicide attack at a munitions attack in the town of Wah in Punjab province left nearly 70 people dead.
The loose alliance of militants that calls itself the Pakistan Taleban claimed responsibility for the Wah incident, the heaviest attack on a military installation by a militant group in the country's history.
Gilani's PPP and Mr Sharif's PML-N have spent much of their time since February arguing over issues such as the power of the presidency and whether judges sacked by former President Pervez Musharraf should be reinstated.
During that time the economy has taken a further battering with the Pakistani rupee falling to an all time low while food and fuel prices have risen sharply.