Under pressure: Robertson

Downing Street has tried to talk down a NATO row over military protection for Turkey, even though the alliance's secretary general said it is a "serious" matter.

British officials said the decision by Germany, France and Belgium to protest against the request by America to place anti-missile defence systems on Turkey's border was part of a discussion and not a veto.

"A veto is only a veto if it results in something that never happens," said the prime minister's official spokesman.

"No-one actually vetoed anything. The breaking of silence allows further discussion to take place and that's what will take place. It's likely this is going to be a matter of continuing conversation."

This came despite the admission by NATO secretary general Lord Robertson that the row was a serious problem.

At a hastily-arranged press conference on Monday, he admitted that there had been disagreements between alliance countries.

Following the decision of the three countries to block the bid, the Turkish government requested renewed discussions under self-defence treaty articles.

Lord Roberson said discussions on the dispute would continue on Monday afternoon in a bid to reach a deal.

"There is an honest disagreement within NATO on when to start contingency planning," he said. "It is serious."

The row is set to further damage relations between Paris and Washington, following the announcement of a Franco-German plan to boost inspections by increasing the number of UN staff in Iraq.

Belgian officials said sending the missiles would "send the wrong signal" at a crucial time.

Experts are warning the row could cause irreparable damage to the transatlantic alliance.

Last week the NATO chief sought to call the bluff of objectors by initiating a "seven day silence" procedure in which members had a chance to object to the measure before it was approved.

But the three European governments angered Washington by blocking help for Turkey.

The US administration has slammed the move as "shameful and inexcusable".

Liberal Democrat foreign affairs spokesman Menzies Campbell warned the NATO move could undermine Hans Blix.

"The case for more time has been unnecessarily undermined by the apparent veto through NATO to provide protection to Turkey," he said.

"As a member of the alliance Turkey is entitled to all of the protection which article five of the North Atlantic Treaty requires. Vetoing the NATO deployment of patriot missiles for Turkey's protection is unnecessarily provocative."