The Pakistani civil aviation authority has shut its airspace to all commercial flights, as tensions with India escalate.

Earlier the Pakistani military said it had shot down two Indian warplanes and captured one of the pilots in Kashmir, in a major escalation of the conflict in the disputed territory.

An army spokesman said the country's air force shot down the jets after they crossed the boundary between the two nuclear rivals in the region.

Major General Asif Ghafoor said one plane went down in Indian-controlled Kashmir and another crashed on its own territory where Pakistani troops on the ground detained the pilots.

He said one of the Indians was injured was being treated in a military hospital and said the other was in custody.

Major Ghafoor said the pair "are being treated well" and did not say if they would be allowed to return home.

It comes a day after Pakistan threatened India with retaliation after its rival launched an airstrike on a suspected extremist training camp in the Pakistan-controlled part of Kashmir.

India said the early morning strike "eliminated" a large number of militants and no civilians were hurt.

Major Ghafoor warned Delhi in a news conference on Tuesday: "It is your turn now to wait and get ready for our surprise."

India said its strike inside Pakistan was to prevent the Jaish-e-Mohammad group from launching another attack on Indian territory.

The Pakistan-based militant group claimed it had carried out a suicide bombing on a convoy of India's paramilitary forces in Indian-controlled Kashmir on February 14th, killing 40 troops.

Last week, United Nations Secretary-General António Guterres called on India and Pakistan to take steps to defuse tensions.

UN spokesman Stéphane Dujarric said: "It is the belief of the Secretary-General that all difficult challenges can be resolved peacefully and satisfactorily through meaningful mutual engagement".

The UN has long maintained an institutional presence in the area between India and Pakistan.

According to a UN Security Council mandate given in 1971, the UN Military Observer Group in India and Pakistan (UNMOGIP) observes and reports on ceasefire violations along and across the line of control and the working boundary between the South Asian neighbours in Jammu and Kashmir.

India has accused Pakistan of allowing the militant group to operate on its territory - which Islamabad denies.

"This was not a retaliation in true sense, but to tell Pakistan has capability, we can do it, but we want to be responsible, we don't want an escalation, we don't want a war," Major Ghafoor said of the latest strikes during a news conference on Wednesday.

In a separate statement, Pakistan's foreign ministry said: "If India is striking at so called terrorist backers without a shred of evidence, we also retain reciprocal rights to retaliate against elements that enjoy Indian patronage while carrying out acts of terror in Pakistan."

Pakistan's civil aviation authority said it had shut its airspace to all commercial flights.

Airspace closure

An Indian air force official said it had ordered the closure of Kashmir's main airport in Srinagar and three others in neighbouring states.

Several Indian airlines announced services to cities including Amritsar, Chandigarh, Dehradun, Jammu, Leh and Srinagar were affected due to airspace restrictions.

IndiGo, GoAir, Jet Airways and Vistara said flights to several airports were on hold or temporarily suspended.

Indian officials said three Pakistani jets had entered Indian airspace and were intercepted and forced to turn back.

Indian Air Force spokesman Anupam Banerjee in Delhi said he had no information on Pakistan's statement.

Senior Indian police officer Munir Ahmed Khan said an Indian Air Force plane crashed in Budgam district in the state of Jammu and Kashmir in Indian-controlled Kashmir and that it was not immediately known if there were any casualties.

Witnesses said soldiers fired in the air to keep residents away from the crash site.

Kashmir has been split between India and Kashmir since the end of British rule in 1947.

The disputed territory has been termed a nuclear flashpoint and both countries have fought three wars over the area.

Tensions between the two nuclear armed neighbours has increased as both sides blame each other for the violence in the region.