An American lawmaker has warned Pakistan's president that U.S. aid to the South Asian nation is in jeopardy.

Representative Michael McCaul, a Republican from Texas, this week led a U.S. Congressional delegation to Pakistan, where he met with President Asif Ali Zardari on Tuesday.

McCaul said he told Mr. Zardari the U.S. relationship with Pakistan must change in light of the discovery that al-Qaeda leader Osama bin Laden was living there — reportedly for several years — before his death. Bin Laden was killed in a U.S. raid in the Pakistani garrison city of Abbottabad May 2.

McCaul said he discussed the idea of increasing trade between the United States and Pakistan as a way to boost long-term trust and advance the countries' mutual interest in fighting terrorism.

The U.S. lawmaker said both he and Pakistan's president described U.S.-Pakistani relations as a “bad marriage where divorce is not an option,” due to the shared threat of extremism that both nations face.

Tension between the two countries escalated following allegations by U.S. officials that Pakistan's military spy agency, or the ISI, was providing support to the militant Haqqani network. The al-Qaida-linked group has launched a number of attacks on U.S. and NATO forces in Afghanistan.

McCaul said that during talks with President Zardari, the Pakistani leader expressed willingness to work with the U.S. against terror groups, such as the Haqqani network. But the U.S. representative questioned Mr. Zardari's ability to carry out the pledge, given the influence of the military in Pakistan.

McCaul is chair of the House U.S. Homeland Security Oversight and Investigations Committee.