The United States and Britain have agreed that any new military defense initiative launched by Europe must be firmly rooted within the NATO alliance. The European Union is considering a military force that could be deployed in crises where NATO does not intervene. Washington, though, is concerned such a force could weaken the trans-Atlantic relationship.

For years, Washington has urged Europe to take more responsibility for its own defense. Now, the European Union wants to do just that by creating a security force of its own. But such a force, stripped of American troops and not under the command of an American general, as NATO's troops have always been, is raising concerns on the U.S. side of the Atlantic. Policymakers fear this could chip away at the solid defense relations Washington maintains with its NATO allies.

It was an issue on the agenda Tuesday in Secretary of State Colin Powell's first meeting with his British counterpart, Robin Cook.

"We can strengthen NATO and not weaken NATO," said Mr. Powell. "We don't want to do anything that weakens NATO. It is the bedrock of the North Atlantic relationship between Canada, the United States and our friends in Europe."

British Foreign Secretary Robin Cook appeared less enthusiastic about a European rapid reaction force than others in Europe have been, stressing NATO is and will remain the cornerstone in transatlantic military ties.

"We both agreed that an increase in Europe's rapid reaction capability could strengthen NATO and we're both determined that this new European capacity should be firmly anchored in NATO," said the British official.

But Europe has concerns of its own over American defense ideas - not only the Bush Administration's plan to review U.S. troop commitments abroad, but also its intention to deploy a nationwide missile defense system. European leaders worry this could decouple Washington from its longstanding pledge to Europe's defense.

Secretary Powell told reporters Washington still has a lot to do to convince its allies that a high-tech system designed to shoot down incoming enemy missiles is the way to go.

"They protect us from these dangerous weapons systems that are in danger of proliferating and I think that if we can make that case, then everybody will want to be a part and play a role in missile defense and so I think the burden is on us to demonstrate that," said Secretary Powell.

As old friends and close allies, both governments did pledge to continue to stand together on many issues where they have cooperated in the past, including re-invigorating the collapsing sanctions against Iraq. British Prime Minister Tony Blair visits the White House in two weeks time, hoping to establish with President Bush the extremely close working relationship he enjoyed with Bill Clinton.