Both Washington and Moscow are concerned about Pyongyang, which on July 5 test-fired six short and mid-range missiles and one long-range missile, the Taepodong-2. All missiles fell harmlessly in the Sea of Japan.

After the meeting, held at the Pike's Waterfront Lodge hotel, Rumsfeld said that US officials are looking into taking "a relatively small number" of ballistic missiles and replacing their nuclear warheads with ones armed with conventional explosives.

"We would be happy to see the Russian government decide to do the same thing," he said.

He said that move "would be a good thing" so that within the next five to 10 years "both of our governments had that additional weapon available in case it that may be needed in unusual circumstance.

"It would be vastly preferable to use a conventional weapon than it would be a nuclear weapon," Rumsfeld said.

Ivanov rejected the idea.

"These plans raise Russian concerns," he said. "I cannot announce right now that Russia will join such an initiative."

"As far as I understand the idea ... (is) to maximumly extend the possibility and potential of the preemptive strikes. There can be different solutions," he said.

Before the meeting Rumsfeld visited Fort Greely, some 150 kilometers (90 miles) from Fairbanks, where US 10 anti-ballistic missiles (ABMs) are positioned in underground silos.

The missiles are a key part of the US missile defense system, designed to shoot down enemy missiles fired at US soil.

The system consists of a network of early-warning satellites, targeting and tracking radars, a command center based in the western US state of Colorado, and missile interceptors deployed in Alaska and at Vandenberg Air Force Base in California.

After the visit Rumsfeld fingered North Korea as a dangerous weapons proliferator.

"I think the real threat that North Korea poses in the immediate future is more proliferation than a danger to South Korea," he said.

The North Koreans "have been among the leading ballistic missile developers in the world and the leading ballistic missile proliferators in the world, working with Iran and with various other countries," Rumsfeld added.

Commenting on North Korea's July 5 tests, Rumsfeld said he believed it was probably important for Pyongyang "to test these things so they can sell them."

Alaska has been chosen as an ABM deployment site because of its geographical location that allows the United States to protect itself against attacks coming from both the East and the West. While the ability of the controversial anti-missile shield to function in real-life conditions is being questioned, US President George W. Bush has insisted it had a reasonable chance of shooting down a missile.

Only five out of 10 tests of missile interceptors have been successful. The last successful one dates back to 2002, but it was followed by two failures.

The US goal is to have 40 interceptors deployed in Alaska in the next years.

In the future, Washington envisions deploying interceptor missiles in Europe. However, the US Congress has not yet appropriated funds for that.

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