Bush welcomed Putin to the Camp David mountaintop retreat with a hug and handshake as Putin stepped off a helicopter. They got into a golf cart and drove away, Bush at the wheel, for talks at a lodge tucked away in the leafy, heavily guarded surroundings.Putin and Bush's last summit was in St. Petersburg, Russia, in June. They planned to have dinner, hold a news conference on Saturday morning, and conclude the visit with lunch.

In addition to Iraq and Iran, US officials said, the two leaders would discuss efforts to contain North Korea's nuclear weapons program and revive the Middle East peace process.

They also were expected to discuss a US effort to persuade governments to join a global effort to stop the spread of weapons of mass destruction.

On Iran, Bush planned to pressure Putin to stop Russian assistance to Tehran's nuclear program amid international concerns Tehran wants to develop weapons, the officials said. Putin has been resisting Bush's pressure.

The International Atomic Energy Agency, at Washington's urging, has raised concerns about Iran's nuclear aims and given Tehran until the end of October to dispel doubts that it is secretly developing nuclear arms.

Putin said last Saturday he has proof that Western firms are also working in Iran's atomic sector.

At the top of their agenda is Iraq, where Bush needs Russian support for a new UN resolution authorizing a multinational force and establishing a path to democracy.

French President Jacques Chirac wants a rapid transfer of Iraqi sovereignty from US control -- France, like Russia, is a permanent member of the UN Security Council -- but Putin appears flexible.

The United States seeks a lengthy period before self-rule in spite of daily guerrilla attacks on US troops and the growing cost of the occupation of Iraq.