The United States has seen evidence that Pakistani militants and affiliated charities are deepening their involvement in flood relief in an effort to win popular support, a senior US official said.
The disclosure follows State Department warnings that insurgents may also be targeting foreign aid workers responding to the floods, and raises the stakes in relief efforts that critics say are moving too slowly.
The worst floods in decades, triggered by unusually heavy monsoon rains more than three weeks ago, have overwhelmed the Pakistani state's ability to respond.
One major risk is Islamist charities and militants successfully exploiting anger over the government response, even as the United States and international allies rush to deliver additional aid.
The senior official, who spoke on condition of anonymity, said militants were even dispensing money for victims.
"There are certainly clear indications that the insurgents and affiliated groups are trying to use the flood and the relief from the flood to try to gain support for their broader effort of being able to control large parts of Pakistan," the official said on Thursday.
Pakistan, aware of the risks, last week announced it would clamp down on charities linked to Islamist militant groups.
But, in a sign of how difficult that could be to do in practice, the top US aid official on Wednesday toured a flood victims camp which had also been supplied by a charity with suspected links to a militant group on a US terrorism list.
The camp was in a government school served by Falah-e-Insaniyat, a charity with suspected ties to Lashkar-e-Taiba and its humanitarian wing Jamaat-ud-Dawa, both blacklisted by the United Nations.
Once nurtured by Pakistan's spy agency to fight India in Kashmir, Lashkar-e-Taiba was blamed for the 2008 attack in the Indian commercial capital Mumbai that killed 166 people.
Aid, money, food
"They're delivering aid. They bring money. They bring food," the official said of the aid efforts by insurgents.
The official acknowledged that the crisis was a lot for Islamabad to absorb, particularly since the country only returned to civilian rule two years ago.
"The scale of the disaster would challenge any government," the US official said.
Pakistan's government is expected to ask the International Monetary Fund during talks in Washington this week to ease restrictions on an $11 billion loan program approved in 2008.
Analysts have questioned whether any backlash against Islamabad could also negatively affect efforts by the United States to boost its image in the country, as it tries to win over support for the battle against militants there and in neighboring Afghanistan.
So far, at least, the reaction has been positive, the official said. But he stressed the extent of fallout from the flooding was still unknown, a view echoed by analysts.
"This is likely to unfold over weeks if not months. It is too soon to predict what the political implications are," said Brian Katulis of the Center for American Progress.
Speculation is rife in Pakistan that the floods may affect the political fortunes of President Asif Ali Zardari, who was criticized for sticking to a European trip while his country was under water.
Former US ambassador to Pakistan, Wendy Chamberlin, cautioned Washington to stay out of any political drama that might unfold and focus on relief efforts.
"Pakistani politics will take its natural course and we should not be involved or play favorites," said Chamberlin, who is with the Middle East Institute.