WASHINGTON - Prospects for a U.S.-Russian partnership on a missile defence system have improved slightly as Moscow grows increasingly concerned about Iran, Defence Secretary Robert Gates said Tuesday.

He told senators that U.S. offers to put radar or data exchange centres in Russia are among the options being discussed.

Gates recounted a meeting he had with Russian Prime Minister Vladimir Putin during which the then-president "basically dismissed the idea that the Iranians would have a missile that would have the range to reach much of western Europe and much of Russia before 2020 or so."

"And he showed me a map that his intelligence guys had prepared," Gates told a Senate Appropriations panel. "I told him he needed a new intelligence service."

He did not say when the meeting occurred.

But Gates added: "The fact of the matter is, the Russians have come back to us and acknowledged that we were right in terms of the nearness of the Iranian missile threat, and that they had been wrong. And so my hope is we can build on that."

Russian and U.S. officials are working intensively on a successor deal to the 1991 Strategic Arms Reduction Treaty, or START I, which expires in December. Negotiators are aiming for some results by July 6-8 when Russian President Dmitry Medvedev hosts President Barack Obama in Moscow.

Obama has delayed previous plans by the Bush administration to build a small missile defence system in Poland and the Czech Republic, with the aim of intercepting missiles from Iran targeted at the West. Russia prefers that Washington scrap the system altogether.

Gates called the chance of making progress toward a deal "somewhat improved" but did not explicitly say why, or what concessions the United States might be prepared to make.

Earlier, Sen. Dianne Feinstein, a Democrat, raised the issue of whether Israel would attack Iran. Gates sidestepped her question on whether that possibility has increased over the last year, but said concern about Iran's nuclear weapons and missile programs certainly has grown.

He said the United States and Israel are wary "given the unwillingness of the Iranians to slow, stop or even indicate a willingness to talk about their programs."

Gates also cited concerns about North Korea's missile program, and repeated his belief that the United States could defend itself against a missile should Pyongyang launch one.

Last week, North Korea moved a long-range missile -- the second in three months -- that some believe could hit the United States. But it's not clear what Pyongyang plans to do with its new system.