The gun battle between Indian troops and militants at an air force base in Pathankot near the Pakistani border has entered its third day.

Indian TV stations reported that a loud explosion was heard at the base on Monday morning.

At least five attackers and seven Indian soldiers have died so far. It is unclear how many militants are still inside the base.

Helicopters have been involved in the operation to secure the base. Photo: AP

Indian PM Narendra Modi held a meeting on Sunday to review the situation.

The attack is being seen as a blow to an apparent Indo-Pakistani peace initiative launched just days ago.
 

Hopes for a thaw in relations were raised after Modi paid an unexpected visit to his Pakistani counterpart, Nawaz Sharif.

Pakistan's foreign ministry and the US State Department have condemned the attack.

The attack started before dawn on Saturday, when a group of gunmen - wearing Indian army uniforms - entered the residential quarters on the base.

Hours of heavy gunfire followed, and a helicopter was seen firing at the facility on Sunday.

The identity of the attackers is not clear. Some Indian security officials suggested the Islamist militant group Jaish-e-Mohammed was to blame.

Gunmen attacked the base at night, entering living quarters. Photo: AP

India says the group is backed by Pakistan, but Islamabad denies this.

In July seven people were killed in a similar attack when gunmen stormed a police station in nearby Gurdaspur district. The three attackers in Gurdaspur were killed after a 12-hour standoff with police.

Pathankot air force base is about 430km (270 miles) north of the Indian capital, Delhi and is on the road linking Indian-administered Kashmir with the rest of the country.

Indian-administered Kashmir has seen a long-running insurgency against rule from Delhi, and Kashmir has been a flashpoint in relations between Pakistan and India for nearly 70 years since independence.