LONDON: The Taliban will escalate their attacks on international forces in Afghanistan if Western political support weakens in the face of the increasingly fierce insurgency, the head of NATO warned Tuesday.

Anders Fogh Rasmussen also told the Daily Telegraph newspaper he could not give a date when forces would leave the war-torn nation and urged troop-contributing countries to keep soldiers there "as long as necessary".

His comments came after a meeting Monday in London with British Prime Minister David Cameron, who last week told lawmakers he hoped to see the country`s troops return home within five years.

"We can have our hopes, we can have our expectations, but I cannot give any guarantee as far as an exact date or year is concerned," the NATO secretary general said.

"The Taliban follow the political debate in troop-contributing countries closely," he said.

"If they discover that through their attacks, they can weaken the support for our presence in Afghanistan, they will just be encouraged to step up their attacks on foreign troops."

NATO and the United States have more than 140,000 troops in Afghanistan with another 10,000 due in coming weeks as part of the counter-insurgency strategy.

Rasmussen further warned that an early departure from Afghanistan could see the Taliban return to power and destabilise its nuclear-armed neighbour, Pakistan.

If international forces left Afghanistan too soon, "the Taliban would return to Afghanistan and Afghanistan would once again become a safe haven for terrorist groups who would use it as a launch pad for terrorist attacks on North America and Europe," he said.

"There would also be a risk of destabilising a neighbouring country, Pakistan, a nuclear power."

Following the NATO chief`s meeting with Cameron, his office said they had "agreed on the central importance" of the NATO mission to its members security.

"The prime minister made clear that success in Afghanistan was his government`s highest foreign policy and national security priority," said a statement.

BDST: 0920 HRS, July 13, 2010