By Qasim Nauman
ISLAMABAD (Reuters) - Pakistan, its ties with powerful ally the United States heavily strained, is looking increasingly isolated after rival India signed a wide-ranging agreement with neighboring Afghanistan.
Pakistan wants a major say in shaping any peace settlement in Afghanistan, where India is taking an active but low-profile approach to building influence through aid and investment.
But Islamabad has alienated both the Washington and Kabul governments -- who will play a central role in any reconciliation -- because of its suspected links with militant groups fighting Western and Afghan forces in Afghanistan.
On a two-day visit to New Delhi, Afghan President Hamid Karzai and Indian Prime Minister Manmohan Singh sealed a strategic partnership on Tuesday that spanned closer political ties to fighting terrorism.
It signals a formal tightening of links that may spark Pakistani concerns India is increasingly competing for leverage in Afghanistan.
"Suspicion will increase, but that's a negative approach," said independent Pakistani political analyst Hasan Askari Rizvi, referring to the Pakistani reaction to the agreement.
"Unfortunately, there is so much Indian obsession in Pakistan that with every minor Indian move, there is panic," he said.
Government spokesmen in Pakistan, which has long feared a hostile India over its eastern border and a pro-India Afghanistan on its western border, were not immediately available for comment.
The agreement with India is one of several being negotiated by Kabul, including one with the United States, that are part of an Afghan bid for greater security as NATO troops head home.
Karzai's visit comes during rising Afghan frustrations with Pakistan.
Senior Afghan officials accused Pakistan's intelligence agency of masterminding the assassination last month of Kabul's chief peace negotiator with the Taliban.
Karzai himself has said there is a Pakistani link to the killing, and investigators he appointed believe the assassin was Pakistani, and that the suicide bombing was plotted in the Pakistani city of Quetta.
India is one of Afghanistan's biggest bilateral donors, having pledged about $2 billion since the 2001 U.S. led-invasion for projects from the construction of highways to the building of the Afghan parliament.
India, which has trained a small number of officers from the Afghan National Army, is offering more security training to Afghanistan.
Even though nuclear-armed India and Pakistan have been trying to improve relations, analysts say Pakistan is desperate to minimize any Indian role in Afghanistan.
To do that, analysts say, Pakistan is looking to the Haqqani Afghan insurgent network to counter Indian sway, a strategy that infuriates Washington.
The top U.S. military officer has accused Pakistani intelligence of supporting an attack allegedly carried out by the Haqqani group, which is close to al Qaeda, on the U.S. embassy in Kabul on Sept 13.
Pakistan, which denies ties with the group, says it is committed to helping all parties secure peace in Afghanistan.
India wants to ensure that a withdrawal of U.S. troops does not lead to a civil war that spreads Islamist militancy across borders. At the same time it is closely watching Pakistan's own efforts to secure its interests in Afghanistan.
Pakistan's long ties to militant groups in Afghanistan are a constant source of concern for India.
It suspects Pakistan of involvement in several major attacks, including two bombings of its embassy in Kabul in 2008 and 2009, seen as warnings from Islamabad to stay away from its traditional "backyard."
Karzai and Singh also agreed to closer cooperation in the strategically key sectors of oil and gas exploration, mining and infrastructure development.
(Writing by Michael Georgy; Editing by Robert Birsel)