Obama, who is on a foreign fact-finding trip and visited Afghanistan over the weekend, described Afghanistan as the central front in the war against terrorism and said the situation there was "perilous and urgent".

Trying to reduce tensions between traditional rivals India and Pakistan could help, he said.

"A lot of what drives, it appears, motivations on the Pakistan side of the border, still has to do with their concerns and suspicions about India," Obama told a news conference in the Jordanian capital Amman.

"We haven't had a conversation between the Indians and the Pakistanis that has been sustained and meaningful about how they can arrive at a more sensible arrangement between the two countries that could relieve some of the pressure and help us go after ... some of these forces along the border regions."

Relations between India and Pakistan, who have fought three wars since independence from Britain in 1947, have become strained again despite an ongoing peace process.

India blames Pakistan for a bombing last week in Kabul that killed 58 people, including two Indian diplomats. It also accuses Pakistan of backing a two-decade-old separatist revolt in Kashmir, which both sides claim in full but rule in part.

For its part, Pakistan suspects Indian involvement in a low level insurgency in the western province of Baluchistan and trouble in the Pashtun tribal region on the Afghan border, where militants have found sanctuary.

Obama, whose Republican opponents say he lacks foreign policy experience, said al Qaeda and the Afghan Taliban militant group were planning more attacks on the United States as well as mounting a growing offensive on the Afghanistan-Pakistan border regions.