Aiming to Mend Ties, Obama and Pakistani Prime Minister Meet ISLAMABAD, Pakistan - President Obama took a symbolic step toward improving ties with Pakistan on Tuesday when he met with Prime Minister Yousaf Raza Gilani on the sidelines of a nuclear summit meeting in South Korea. But even as the two leaders made polite, if freighted, comments about improved cooperation, harsh debate in Pakistan's Parliament on Tuesday made clear that there may be very little political upside for any Pakistani warming toward Washington. Speaking in Seoul, President Obama acknowledged "strains" in the relationship and voiced his support for a parliamentary review process in Pakistan that aims to get the relationship back on its feet. "I think it's important for us to get it right," he said at a joint news conference. But Mr. Obama added that Pakistan must also respect pressing American security concerns centered on "national security and our needs to battle terrorists who have targeted us in the past." Mr. Gilani replied that he would help work with Mr. Obama "to have all the peace, prosperity and progress of the whole world." Relations between the two countries plunged steeply after the American commando raid that killed Osama bin Laden last May, then worsened further after American warplanes fired airstrikes that killed 24 Pakistani soldiers along the border with Afghanistan in November. The border strikes caused Pakistan to close NATO supply routes into Afghanistan and expel American officials from a remote air based used by the C.I.A. to launch drone strikes against militants from Al Qaeda and the Taliban in the northwestern Pakistani tribal belt. More recently, a Pakistani parliamentary committee on national security demanded an end to drone strikes and an unconditional American apology for the airstrikes. In Islamabad on Tuesday, Parliament was supposed to start a long-awaited debate that would pave the way toward re-engaging diplomatically with the United States. But the opposition stalled the debate, with some lawmakers expressing fury at news reports that the government had already promised to reopen the NATO supply lines. Ayaz Amir, an influential lawmaker with the opposition Pakistan Muslim League-N party, questioned why Pakistan even bothered blocking the supply routes if it was assumed they would start right back up again. "We are fooling ourselves, and we are also fooling the Pakistani people," he said. The most scathing criticism came from Maulana Fazalur Rehman, an influential religious politician, who warned that if the government failed to win broad political backing for its review of American ties, he would take his protests onto the streets. "We will not let such a decision to be implemented in the field," he said. Mr. Rehman asserted that given urgent efforts by the Americans to start negotiations with the Taliban in Afghanistan, American weapons transported through NATO supply lines could ultimately be turned back on Pakistan, earning loud applause from fellow lawmakers. And he asked how the government intended to bring covert American operations in Pakistan under the law of the land. Raza Rabbani, a senior government lawmaker, responded that the parliamentary committee's recommendations on American policy were "broad policy guidelines" and not a final decision. The session was adjourned until Wednesday evening, when the formal debate is due to begin. Meanwhile, outside Parliament, a newly formed alliance of religious parties and extremist groups, the Defense of Pakistan Council, held a large street rally against the reopening of the supply routes. "If Parliament compromises on the security and sovereignty of the country, then we cannot guarantee the security of the lawmakers," said Maulana Sami ul-Haq, head of the alliance, as hundreds of protesters chanted anti-American slogans. Mark Landler contributed reporting from Seoul, South Korea.