Pakistan has released on Friday an Indian fighter pilot seized earlier this week amid days of fighting between the two nuclear powers.

Indian Wing Commander Abhinandan was escorted across the Pakistan-India Wagah border crossing at night time after a long delay. Pakistani authorities have not provided a reason for the pilot's late handover.

Crowds have gathered at the border to watch and celebrate the release of Abhinandan.

Indian Air Force Vice Marshal Rjk Kapoor told reporters “We are happy that our pilot, who had fallen across the line of control and was in the custody of Pakistan, is being released.”

People ride motorbikes before the arrival of Indian Air Force pilot, who was captured by Pakistan on Wednesday, near Wagah border, on the outskirts of the northern city of Amritsar, India, March 1, 2019 Reuters

But India remains on high alert to respond to what defines as a possible provocation of Islamabad.

Tensions between India and Pakistan escalated after a February suicide attack that killed at least forty Indian policemen.

India then said it hit a training camp for an armed group who claimed responsibility for the attack.

Pakistan dismissed the attack as a failure.

The capture of the pilot came a day after India carried out airstrikes against what it said was a militant camp in Pakistan. The airstrikes led to the closure of dozens of airports in the subcontinent.

Indian newspaper ran headlines on Friday focused on the release of the pilot.

“Abhi Coming Home, India Won’t Budge On Terror”, said The Times of India.

READ MORE: What is the tension between Pakistan and India all about?

Pakistan media also claimed the gesture as a “Moral Victory”, according to The Nation newspaper.

Pakistan’s airspace is set to reopen on Friday after it had closed down on safety grounds amid the escalation of violence between Pakistan and India.

The country’s foreign ministry said it will not attend the Organization of Islamic Conference of Foreign Ministers in Abu Dhabi this week because of “unresolved disputes” with India.

The Kashmir region has been disputed territory ever since the end of British colonial rule saw the partition of India in 1947. Both India and Pakistan administer parts of the area but claim full control.

Both sides accuse the other of breaching a ceasefire and no sign yet of any de-escalation of hostilities. Pakistan says it will free a captured Indian pilot this Friday.

Wing Commander Abhinandan Varthaman has been shown on TV, looking bruised and confused.

India welcomed Pakistan's decision to release its pilot despite the Pakistani Prime Minister Imran Khan failing to say whether the release was conditional.

However, on Friday, India's Minister of State for External Affairs Vijay Kumar Singh said on Twitter that Pakistan "has not done us a favor" by returning the pilot.