NEW YORK - In the absence of a US-Pakistan deal so far to reopen the routes for NATO supplies to Afghanistan, President Asif Ali Zardari was preparing to leave Chicago empty-handed, The New York Times reported Monday.

In a front-page dispatch, the newspaper said the the failure to strike the deal with Pakistan was casting a long shadow over NATO summit aimed at ending the alliance's combat role in the Afghan war.

US President Barack "Obama remained at loggerheads with President Asif Ali Zardari of Pakistan, refusing even to meet with him without an agreement on the supply routes," the Times said. It also cited officials in both countries as saying a deal would not be coming soon.

"Mr. Zardari, who flew to Chicago with hopes of lifting his stature with a meeting with Mr. Obama, was preparing to leave empty-handed as the two countries continued to feel the repercussions of a fatal American airstrike last November, for which Mr. Obama has offered condolences but no apology," the dispatch said.

Zardari did, however, meet with Secretary of State Hillary Rodham Clinton to discuss the supply routes.

Twenty four Pakistani soldiers were killed when NATO helicopters fired at two border posts in November, causing a huge strain on the bilateral relationship.

“This whole breakdown in the relationship between the U.S. and Pakistan has come down to a fixation of this apology issue,” Vali Nasr, a former State Department adviser on Pakistan, was`quoted as saying. The combination of no apology and no meeting, Nasr said, “will send a powerfully humiliating message back to Pakistan.”

American officials hope the summit of the 28-member alliance will set in motion an orderly conclusion of the decade-long war in Afghanistan, according to the Times. a huge undertaking. NATO aims to give Afghan forces the lead in combat operations next year to pave the way for the departure of NATO troops by the end of 2014. The NATO summit will also focus on financing Afghan forces for the next several years.

In a sign of the tensions surrounding Afghanistan, hundreds of protesters took to the streets of Chicago on Sunday in opposition to the war and to NATO. The police clashed with some demonstrators who refused to disperse after a march down Michigan Avenue to McCormick Place, where world leaders were meeting.

Obama and his other tenuous ally in the region, President Hamid Karzai of Afghanistan, huddled together Sunday morning to grapple with stalled reconciliation talks with the Taliban.

"It was a measure of just how bad things have gotten between the United States and Pakistan that, by contrast, Mr. Obama’s relationship with Mr. Karzai — which has been rocky ever since Mr. Obama came into office vowing to end what he viewed as former President George W. Bush’s coddling of the mercurial Afghan leader — looked calm and stable on Sunday," tghe dispatch noted.

U.S. and Pakistani officials expressed optimism last week that an agreement on reopening of supply routes was imminent. It was hoped that an invitation for Pakistan to attend the summit would help in bridging the gap between the two sides, the newspaper said.

The failure to strike a deal on the supply routes ahead of the summit injects new tension into the relationship. "When NATO extended the invitation, we thought it would move the Pakistanis off the dime," a senior American official said.

Without the deal, "it''s going to be really uncomfortable" for Mr. Zardari at the summit, which will end on Monday, he added.

American officials said the main sticking point was the amount NATO would pay for each truck carrying supplies from Karachi to the Afghan border. Before the closing, the payment per truck was about 250 dollars. Pakistan is now asking for "upward of 5,000 dollars" for each truck, the official said.