UPDATE 3-Pakistan says Indian warplanes violated airspace

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By Sheree Sardar

ISLAMABAD Dec 13 (Reuters) - Pakistan said on Saturday that Indian warplanes had violated its airspace but said this was "inadvertent" and there was no cause for alarm about an escalation of tension between the nuclear-armed neighbours.

In New Delhi, an Indian Defence Ministry spokesman said he had no information on the reported incursion.

A Pakistani airforce spokesman said there were two violations, one in the Kashmir area and another in the sector around the city of Lahore in Pakistan's Punjab province.

"We have confirmed it. We have spoken to the Indian airforce and they have said it was inadvertent," Pakistan Information Minister Sherry Rehman said.

"Our air force is on alert and ready to face any eventuality, but we do not expect this to escalate," Rehman said. "There is no need for alarm."

Tensions have risen between India and Pakistan following an attack on Mumbai two weeks ago that the Indian government blamed on militants based in Pakistan.

But India has been extremely careful in recent years to prevent its warplanes from straying into Pakistan's airspace.

Its response so far to the Mumbai attacks has focused on persuading Pakistan -- backed by pressure from the United States -- to crack down on Pakistani-based militant groups rather than launching any retaliatory strikes of its own.

India and Pakistan have fought three wars and went to the brink of a fourth in 2002.

India has blamed Pakistan-based militant group Lashkar-e-Taiba (LeT) for attacks on Mumbai last month that killed 179 people.

LeT and a charity linked to the group are both strongly represented in areas around Lahore and in Kashmir.

Pakistan has rounded up some of the 40 people India has demanded should be extradited for the Mumbai killings, but says that India has not provided any evidence of links to the attacks.

According to a newspaper report last week, Pakistan put its forces on high alert during the Mumbai attacks after someone pretending to be India's foreign minister made a phone call to President Asif Ali Zardari threatening war. (Reporting by Sheree Sardar and Kamran Haider; writing by Simon Cameron-Moore; Editing by Myra MacDonald)