MUNICH (Reuters) - New U.S. Defence Secretary Donald Rumsfeld has promised Europeans that Washington will not act alone on plans for a controversial national missile shield and will help its allies deploy such defences.

"The United States has no interest in deploying defences that would separate us from our friends and allies," he told the annual Munich Conference on Security Policy.

"Let me be clear to our friends in Europe: we will consult with you," Rumsfeld said. He also met privately with the defence ministers of France, Britain, Germany and Italy.

The first top official of the new government of President George W. Bush to visit Europe and address the touchy issue, Rumsfeld reiterated that the United States did intend to build a national missile defence (NMD) against limited attack from such states as North Korea, Iran and Iraq.

"A system of defence need not be perfect. But the American people must not be left completely defenceless," Rumsfeld said.

"The United States intends to develop and deploy a missile defence designed to defend our people and forces against a limited ballistic missile attack, and is prepared to assist friends and allies threatened by missile attack to deploy such defences."

NO TIMETABLE

He gave no timetable for such a defensive system. Two of the last three tests have failed, and critics say such a scheme would cost in excess of $60 billion.

In an interview with reporters travelling with him, Rumsfeld also attacked support for the 1972 Anti- Ballistic Missile (ABM) Treaty - which prohibits national missile defences - as "Cold War thinking."

Despite bitter opposition from Russia and China to the NMD plan, Rumsfeld said, it "just doesn't threaten anyone."

Several European leaders say the ABM treaty, which Rumsfeld in December called "ancient history," is a bedrock of nuclear arms control and are worried Washington will abandon it.

German Chancellor Gerhard Schroeder reiterated his strong reservations about NMD to the conference, urging that Washington and its allies "look for joint answers to the existing and new threats to security" within the current arms control framework.

German Defence Minister Rudolf Scharping also stressed during a meeting with Rumsfeld that missile defence had to be discussed in the context of the full 19-member NATO alliance, according to a senior Pentagon official.

Rumsfeld told reporters that Moscow, which has rebuffed U.S. efforts to amend the ABM treaty, was lobbying in Western Europe and around the world to kill the U.S. scheme.

He declined to say whether he felt the ABM treaty should be modified, or scrapped.

On another issue of concern to Europe, Rumsfeld said Washington had no intention of moving precipitously to withdraw U.S. peacekeepers from the Balkans.

But he said the United States and its allies would continue studies to determine how and when forces in Kosovo and Bosnia could be reduced.

U.S. Senators Joseph Lieberman of Connecticut and John McCain of Arizona told the conference that there was broad bipartisan agreement among Americans favouring missile defence.

"This is not a technologically feasible programme now," said Lieberman, a Democrat who lost in the race for vice president to Republican Dick Cheney. "We have time, so let the debate begin."

Rumsfeld told the conference that he was open-minded about the European Union forming its own rapid-reaction force to deal with conflicts or peacekeeping in which NATO was not involved, but warned the force must not weaken NATO's power or status.

"Weaken NATO and we weaken Europe, which weakens all of us," he cautioned.