LONDON -- Senior officials with the Obama administration tell ABC News that this morning, after a bilateral meeting between President Obama and Russian President Dmitry Medvedev, the governments of both countries will make a major announcement relating to U.S.-Russian relations, including arms control, a statement of the future U.S.-Russian agenda and a U.S.-Russian summit to take place perhaps as early as this summer.
"There are very real differences between the United States and Russia, and I have no interest in papering those over," President Obama said Wednesday morning at a press conference with British Prime Minister Gordon Brown. "But there are also a set of common interests."
The President listed those interests as ranging "from Afghanistan to Iran ," including "reducing nuclear stockpiles … reducing the threat of terrorism ... stabilizing the world economy … and finding a sustainable path for energy and dealing with some of the threats of climate change. ... I think there's great potential for concerted action and that’s what I think we'll be pursuing."
"A good place to start will be the issue of nuclear proliferation," the president said.
The announcement will include a set of instructions to arms negotiators on how to conclude a new, "post-START" agreement by the end of 2009, a senior official tells ABC News.
START -- or the Strategic Arms Reduction Treaty -- between the United States and then-USSR was signed in March 1991 and removed more than 75 percent of the strategic nuclear weapons in both countries' arsenals.
But START is set to expire Dec. 5, 2009.
Russian leaders have been making a lot of noise about rearming Russia; Russian Strategic Rocket Force Commander Nikolai Solovtsov, for example, said that Russia would start deploying next-generation RS-24 missiles after START expires at the end of the year.
Wednesday's announcement could put the United States and Russia on a path to prevent that rearming. It will not be a treaty, the official cautioned ABC News. "This is just a set of instructions on how negotiators need to proceed."
An Obama administration official says that the goal of the post-START negotiations would be to roughly reduce the joint u.S.-Russian nuclear arsenal to 3,000 missiles from the current allowable level of 4,400.
The announcement will also include a joint statement on U.S.-Russian relations. The statement will include a section on arms control, Iran, Afghanistan, European security, the United States' proposed missile defense shield, the Russian war with Georgia, the World Trade Organization, democracy and human rights.
"It will cover a big agenda -- setting the agenda for us to try to do more things in a more comprehensive cooperative way with the Russians," the official said. "One notion will be we should look at cooperative ways to look at defense.
"Nobody's going to be looking into anybody's soul tomorrow," the official said, referring to President George W. Bush's testimony about former Russian President Vladimir Putin. "We'll deal with concrete issues where we can cooperate, and we will also recognize our disagreements."
The officials described the document as dealing with "very concrete substantive issues, not 'preamble' language or high-flying rhetoric, no discussion of being allies or strategic partnerships."
The official described U.S. negotiators as being "very sober-minded. ... We're starting at a pretty bad place with U.S.-Russian relations. You'd have to go back to 1983 to remember a time when relations were so confrontational. And they're not now."
The process began with the letter President Obama wrote to Medvedev in February, in which the president acknowledged the deterioration of relations between the two countries and suggested that U.S. plans for a missile defense shield to protect European allies -- a shield fiercely opposed by the Russians -- wouldn't be necessary if Iran's nuclear weapons program were no longer an issue.
"What I said in the letter was that, obviously, to the extent that we are lessening Iran's commitment to nuclear weapons, then that reduces the pressure for, or the need for, a missile defense system," Obama said.
The letter was followed up with negotiations and discussions with Russian government officials by various U.S. officials, including Secretary of State Hillary Clinton -- who met Tuesday with Minister of Foreign Affairs of the Russian Federation Sergey Viktorovich Lavrov; Under Secretary of State for Political Affairs William Joseph Burns; and Michael McFaul, special assistant to the president for National Security Affairs and senior director of Russian and Eurasian affairs at the National Security Council.
-- Jake Tapper