As President Obama and other NATO leaders wrap up a two-day summit today in Chicago, the ongoing dispute with Pakistan over reopening supply routes from that country into Afghanistan threatens to "put a crimp in the Obama administration's efforts to lay out a clear strategy for winding down the war in Afghanistan," NPR's Jackie Northam tells our Newscast desk.

As Jackie adds, Pakistan still hasn't agreed to let NATO use the routes — which Pakistan closed about six months ago after 24 of its solders were killed by fire directed their way by NATO forces across the boarder in Afghanistan. NATO officials have said there was confusion about whether Pakistani troops were in an area thought to be controlled by militants.

Pakistani President Asif Ali Zardari was invited to the Chicago summit in the hope that an agreement could be reached on the supply routes. But Jackie reports that many details still need to be worked out, including the price-per-truck NATO will pay for access to the routes.

Zardari has also pressed for a "permanent solution" concerning U.S. drone strikes on suspected militants in Pakistan, which have also killed some civilians.

The BBC adds that at the summit, NATO leaders are "expected to endorse plans to hand over combat command to Afghan forces by mid-2013 and seek progress in opening routes for troop withdrawals. They also hope to reach a commitment on who pays how much towards funding Afghan forces after 2014."

NPR's Scott Horsley rounded up the news from Chicago for Morning Edition.

Update at 1 p.m. ET. Both Sides Try To Apply Leverage.

From Islamabad, NPR's Julie McCarthy tells us more about the supply route dispute:

The issue is: how much is the U.S. willing to pay Pakistan, which knows knows that NATO is paying a high price to move supplies into Afghanistan via routes to the north, toward Russia — much higher costs than if it were moving goods thru Pakistan. Pakistan has factored that into its calculation.But from the U.S. point of view, the proposed price on the table is many times what the Americans are willing to pay. So there's a stalemate.Pakistan's leverage is that the U.S. also needs to get out of Afghanistan in the next couple years and Pakistan is the fastest way out. The U.S. leverage is that it will hold up some $1 billion dollars in badly needed aid, unless the routes are re-opened.Copyright 2016 NPR. To see more, visit http://www.npr.org/.