Moscow ? Presidents Barack Obama and Dmitry Medvedev end a seven-year hiatus in U.S.-Russian summitry today, with each declaring his determination to further cut nuclear arsenals and repair a badly damaged relationship.

Both sides appear to want to use progress on arms control as a pathway to possible agreement on trickier issues, including Iran and Georgia, the tiny former Soviet republic. Those difficulties and others have soured a promising linkage in the first years after the Cold War and pushed ties between Moscow and Washington to depths unseen in more than two decades.

In advance of Obama’s departure Sunday, a White House official told reporters the presidents expect to announce progress on negotiations that could lead to a treaty to replace the START I agreement, which expires on Dec. 5.

More broadly, the U.S. wants to use the summit to overhaul the U.S.-Russian relationship.

“It’s not, in our view, a zero-sum game, that if it’s two points for Russia it’s negative two for us, but there are ways that we can cooperate to advance our interests and, at the same time, do things with the Russians that are good for them as well,” Obama’s top assistant on Russia, Michael McFaul, said in a presummit briefing.

Medvedev said in an Internet address that the two powers “need new, common, mutually beneficial projects in business, science and culture. He added, “I hope that this sincere desire to open a new chapter in Russian-American cooperation will be brought into fruition.”

Two things appear certain:

l The Russians have said they will agree to allow the United States to use their territory and air space to move munitions and arms to U.S. and NATO forces fighting Taliban extremists in Afghanistan. The Kremlin announced the deal days before the summit as a sweetener for Obama.

l A directive for negotiators to work toward a START I replacement. Both sides are agreed in principle to cut warheads from more than 2,000 each to as low as 1,500 apiece.

Those deals could be announced at an Obama-Medvedev news conference this afternoon following the leaders’ scheduled four-hour meeting.