Russia and the United States pledged on Sunday to prevent nuclear, biological and chemical weapons being used for terrorism and to stop money funding those involved.
In a joint statement released after US President Mr George Bush and Russian President Mr Vladimir Putin held more than an hour of talks, the two nations said they would co-operate in many fields in the anti-terrorism fight.
The statement also urged the formation of a coalition government in Afghanistan, the target of three weeks of US air strikes and at least one ground operation. The coalition should include groups that would bring stability, the statement said.
"The presidents of the two countries are fully resolved to increase co-operation in the fight against new terrorist threats in the nuclear, chemical and biological fields, as well as in the field of computers," said the statement, released by the Kremlin after the leaders held a news conference in Shanghai.
Mr Bush and Mr Putin met after taking part in a weekend summit of leaders from the Asia Pacific Economic Co-operation (APEC) grouping. APEC leaders issued an unprecedented anti-terrorism statement but the Russian-US declaration went further.
"They agreed to increase bilateral and multi-lateral actions to prevent the export and distribution of nuclear, chemical and biological materials, the technology connected with them and the means for their delivery," the US-Russian statement said.
With an anthrax scare sweeping the US in the wake of the launch of the strikes on Afghanistan, the issue of biological and chemical warfare has been on the minds of many. However, it is not clear who is sending letters containing anthrax spores in the US.
Bush has said there is no firm evidence linking them with Osama bin Laden, the Saudi-born militant accused of masterminding the September 11th attacks on Washington and New York.
Anthrax is potentially deadly bacteria that can be used in germ warfare.
The two leaders said they would strike at the roots of groups involved in terrorism by choking off their funding.
"The presidents agreed that the networks of financing, communications, organisational and technological support of terrorist organisations should be destroyed," it said, calling on other nations to help the US and Russia in this.
Russia, a signatory of the international chemical weapons convention, has said nations that do not sign the pact are promoting terrorism.
Russia itself has the biggest stockpile of chemical weapons, inherited from the Soviet Union.
It aims to destroy its 40,000 tonnes of chemical warfare agents by 2012.
Russian officials say the US has around 32,000 tonnes of chemical weapons.
The statement issued by the two leaders also reiterated that a new government in Afghanistan should be formed that would have good relations with its neighbours and the rest of the world.
"The presidents stress that the current situation in Afghanistan is a direct result of policies carried out by the Taliban, who turned the country into an international centre for terrorism and extremism," the declaration said.