The release of an Indian pilot by Pakistan would be a "very much welcomed step", spokesperson for UN chief Antonio Guterres said Thursday, stressing that the message to India and Pakistan from the world body and the international community is to de-escalate tensions.

In a surprise announcement during a joint session of Parliament, Prime Minister Imran Khan said on Thursday that captured Indian Air Force pilot Wing Commander Abhinandan Varthaman will be released on Friday as a gesture of peace.

Pakistan detained Wing Commander Varthaman on Wednesday following a fierce engagement between air forces of the two sides along the Line of Control when his MiG 21 fighter jet was downed.

"The reports of the promise of the release of the Indian pilot by the Pakistani authorities would be a very much welcomed step," the spokesperson for the UN Secretary-General Stephane Dujarric told reporters here.

"We would encourage both parties to do whatever they can to de-escalate the situation and this is the message that has been passed on by the UN and by the international community as a whole," he said.

Asked whether the Secretary-General spoke with the Prime Ministers of India and Pakistan amid the escalating tensions between the nuclear-armed South Asian neighbours, Dujarric said: "contacts have been had with both sides at various levels". He did not give further details.

Guterres has been following with "deep concern" the escalating tensions between India and Pakistan, calling on both sides to urgently take steps to lower tensions through "meaningful mutual engagement".

The Secretary-General is "obviously, following the situation as we see it even today with deep concern, and the United Nations' message, both publicly and privately, to both sides is to urgently take steps to lower tensions through meaningful, mutual engagement and meet their responsibilities to maintain peace and security in the region," Dujarric had said on Wednesday.

Guterres had received a call on Tuesday from Pakistan's foreign minister Shah Mahmood Qureshi.

When asked if the Secretary-General is planning to get involved to try and mediate a de-escalation, Dujarric had said "as always", the Secretary-General's offices are "available should both parties or all parties, depending on the situation, agree to do that".

The spokesperson said the UN chief, through his contacts and others, is in touch with the relevant parties to pass along the message of the need to take steps to lower tensions and exercise maximum restraint.

Dujarric said contacts have been made at various levels between the UN, India and Pakistan, but did not give further details as to which officials in India were contacted.

Asked about the UN's role at this point in the situation, he said that the Secretary-General is "kept apprised" of the situation and he is following it.

Tensions have escalated between India and Pakistan in the wake of the Pulwama attack claimed by Pakistan-based terror group Jaish-e-Mohammed (JeM). Forty CRPF soldiers were killed in the suicide attack in Jammu and Kashmir.

India carried out air strikes against the biggest training camp of JeM in Balakot. In the operation, a very large number of JeM terrorists, trainers, senior commanders and groups of jihadis who were being trained for suicide attacks were eliminated.

Pakistan on Wednesday claimed it shot down two Indian fighter jets over Pakistani air space and arrested a pilot.