KABUL, Afghanistan - Russia is ready to cooperate on defense matters with Afghanistan, the Afghan president said Monday. The announcement coincides with increasingly public tensions between Afghan and Western officials, as well as Russia's heightened efforts to assert itself on the international stage.

In a letter, Russian President Dmitry Medvedev said cooperation on defense issues would "be effective for both countries and also effective for maintaining security in the region," Afghan President Hamid Karzai's office said in a statement.

"As a friendly government to Afghanistan, Russia is ready to offer its cooperation to an independent and a democratic Afghanistan," the statement quoted Medvedev as saying.

The statement did not say how the two countries would cooperate, but historically they have been at odds. Russian soldiers were part of the Soviet Army that occupied Afghanistan throughout the 1980s, before being forced to withdraw in 1989 following years of a U.S.-supported insurgency that drained Soviet resources and contributed to the country's collapse.

A spokesman at the Kremlin in Russia said he had no detail about the exchange between Medvedev and Karzai.

Moscow has little to gain if the U.S. and NATO fail to defeat the Taliban and install a strong central Afghan government, and says it wants stability in Afghanistan. The relationship between NATO and Russia has been delicate for years, but Russia in November allowed Spain and Germany to use Russian rail lines to ship supplies for their forces in Afghanistan.

Gen. David Petraeus, the chief of the U.S. Central Command, said Monday that the U.S. has secured agreements to transport equipment for troops in Afghanistan through Uzbekistan, Kazakhstan, and Russia.

But Russia is also eager to boost its arms sales, raise its global profile and boost its prestige.

The correspondence from Karzai - on the eve of U.S. President-elect Barack Obama's inauguration - comes as Afghan officials are fighting criticism that Karzai's government is weak and corrupt.

The U.S. has said it will send up to 30,000 new troops into Afghanistan in 2009, including some 3,000 forces in two provinces adjacent to Kabul, where militants now have free rein. The U.S. now has some 32,000 troops in Afghanistan.

U.S. Secretary of State-designate Hillary Clinton recently used the term "narco state" to describe Afghanistan in recent written Senate testimony, a choice of words that drew the ire of Afghan officials. Foreign Minister Rangin Dadfar Spanta told The Associated Press over the weekend that the use of the term was "absolutely wrong" and suggested the drug trade in the country's south was a result of the presence of NATO forces there.

NATO Secretary-General Jaap de Hoop Scheffer wrote in an opinion column Sunday that the West has paid enough in blood and money "to demand that the Afghan government take more concrete and vigorous action to root out corruption and increase efficiency."

In the country's latest violence, a roadside bomb struck a police vehicle in southern Helmand province's Gereshk district on Monday, killing two policemen and wounding three civilians, said Daud Ahmadi, a spokesman for the provincial governor.

Separately, a suicide car bomb attack near the gates of a U.S. base in eastern Afghanistan on Monday killed one Afghan civilian and wounded six more, officials said.

The attack targeted Forward Operating Base Chapman in Khost City, near the border with Pakistan, said Lt. Cmdr. James Gater, a spokesman for the NATO-led mission in Afghanistan.

A second suicide bomber was waiting for emergency officials to respond to the first attack, but he was detected by police and detonated his explosives early, killing only himself, the Interior Ministry said in a statement.

Violence has been rising across Afghanistan the last two years. Obama has promised to increase America's focus on the deteriorating situation in the country while decreasing troop levels in Iraq.