Russia is calling on Afghanistan and other central Asian nations to take more responsibility for the fate of the volatile region.

Russian President Dmitry Medvedev spoke Friday after meeting the leaders of Afghanistan, Pakistan and Tajikistan in the Tajik capital, Dushanbe.

Mr. Medvedev also announced Russia and Tajikistan will sign a deal to extend Russia's use of a military base there for another 49 years.

Tajikistan and Pakistan, which both share borders with Afghanistan, are concerned about regional unrest after the United States pulls its troops out of Afghanistan.

Moscow's deal with Tajikistan secures a base of operation for about 6,000 troops — the military's largest deployment of troops outside of Russia.

Russia has also been in talks with Tajik President Emomali Rakhmon about sending troops back to the lengthy Tajik-Afghan border.

Russian officials worry the porous border is serving as a conduit for Afghan heroin smugglers and for radical Islamists.

Afghan President Hamid Karzai and Pakistani President Asif Ali Zardari also attended the four-nation summit.

The leaders stated their support for Afghanistan's attempts to push for national reconciliation, and welcomed the beginning of the process of transfer of security responsibilities to the Afghans.

The four nations also hope to enhance economic cooperation to enhance regional trade and implement joint projects in energy, transport, communications and infrastructure development.