The Pakistan Air Force (PAF) has been put on alert for "aggression", local television quoted a spokesman yesterday.

The PAF remained focused on the Indian situation and Pakistan was all the time ready for the security and safety of its airspace, the private Geo TV quoted the PAF spokesman Humayun Waqar Zephyr as saying.

Tensions between Pakistan and India are mounting as the Indian side accused Pakistan-based militant groups of involvement in the terrorist attack in India's financial center, which killed more that 170 people and injured over 200.

Indian media reported yesterday that the Indian air force had been put on high alert.

Also on Wednesday, a Pakistan navy spokesman said the navy was put on alert to closely watch India's movement at sea.

But analysts said that the situation between the nuclear-armed rivals has not reached at a point of any confrontation.

"If there is any provocation in India, you will have to use diplomacy. We have used friends to defuse tension. We have also used our foreign ministry," Pakistani Prime Minister Yousaf Raza Gilani told reporters in eastern city of Multan yesterday.

"Pakistan is a responsible state. Being a nuclear power, we are cautious in reaction," Gilani said.

The Pakistani prime minister said that Pakistan would carry out joint investigation into the Mumbai attacks.

Gilani confirmed that Pakistan has arrested two commanders of the banned outfits, blamed by India for Mumbai attacks last month: Zaki-ur-Rhman Lakhvi, chief operational commander of the banned Lashkar-e-Taiba, and Maulana Masood Azhar, leader of the group Jaish-e-Muhammad.