Islamic extremists have resumed small-scale incursions into Indian-controlled Kashmir with Pakistan's tacit support, several militant groups said Friday, threatening to raise tensions over the disputed Himalayan region.

The acknowledgment comes one day after the U.S. ambassador to India said infiltration of militants from Pakistan's portion of Kashmir into India had increased over the past two months, after a period of decline.

The incursions have for years been a source of conflict between the nuclear-armed neighbors.

A militant belonging to Al-Omar, a small guerrilla group operating in the region, told The Associated Press that dozens of fighters have moved quietly and mostly unhindered across the Line of Control and into the Indian part of the province.

"We do not face many problems despite the presence of Pakistani troops," he said on condition of anonymity. "Now our fighters are present in a sizable number in Kashmir."

A member of one of the largest Kashmiri fighting groups, Lashkar-e-Tayyaba, also speaking on condition of anonymity, said his fighters had discovered new entry points into the region free of Indian or Pakistani troops.

New Delhi blames Lashkar-e-Tayyaba and another militant group, Jaish-e-Mohammed, for a Dec. 13 attack on the Indian parliament along with help from Pakistan.

The two countries nearly went to war after the attack, and more than a million troops are still deployed along their borders. Tensions eased amid intense international mediation. Pakistan and India have fought three wars, two over Kashmir, since gaining independence from Britain in 1947.

India accuses Pakistan of training, funding and arming the militants, whose campaign has left more than 60,000 dead since 1989. Pakistan says it gives only moral, diplomatic and political support to the groups.

On Thursday, Pakistani President Pervez Musharraf denied that incursions into the Indian portion of Kashmir had increased. As a result of international pressure, Musharraf vowed earlier this year to curb cross-border terrorism, but also said it was not possible to stop all militants from crossing the border.

Masoud Khalid, a Cabinet minister in Pakistan-controlled Kashmir, said his government has not restricted the movement of Islamic militants looking to cross into Indian territory.

"Kashmiris have every right to move freely on the Line of Control," he said.

Salim Hashmi, spokesman for the United Jihad Council, an association of 15 militant groups, said there had been no official signal from Islamabad encouraging the raids. "The Pakistan government has not given any concession to us in this regard," he said.

But he acknowledged his group, Hezb-ul Mujahedeen, possessed "mobile training camps" inside Indian territory.

He refused to say how the organization's men were being sent into Kashmir, insisting the fighters had found ways to outmaneuver Pakistani troops guarding the border.

"We also know how to continue the struggle against India despite the presence of 700,000 Indian troops in India-occupied Kashmir," he said.