U.S. President Barack Obama has completed his visit to Russia and left for Italy to attend the Group of Eight summit in the city of L''Aquila.

Russian President Dmitry Medvedev will also travel to L''Aquila, where an earthquake killed almost 300 people in early April, later in the day.

Over the two days of his first official visit to Russia Obama met with Medvedev and Russian Prime Minister Vladimir Putin. The U.S. leader also gave a speech to graduates of the New Economic School and addressed a bilateral business forum.

The major achievement of the summit was the signing by Obama and Medvedev on Monday of a preliminary agreement to cut their countries'' nuclear arsenals to 1,500-1,675 operational warheads and their strategic delivery systems to between 500-1,100 units.

The two countries also signed a deal on military transits to Afghanistan, which will allow Russia to inspect U.S. military planes flying over its territory.

Presidential aide Arkady Dvorkovich described on Tuesday the Medvedev-Obama agreements as significant, with the Kremlin expressing the hope that the Russia-U.S. summit would provide momentum for truly large-scale cooperation between the two countries.