OSLO, Oct 31 (AFP) - Norway will put its military on a raised level of alert from Tuesday, moving more personnel on to operational duties and enhancing the role of a rapid mobilisation force in response to the war in Ukraine, the government said on Monday.

Norway will also seek to bring its new fleet of U.S.-made P-8 Poseidon submarine-hunting maritime patrol aircraft into regular operation at a faster pace than originally planned, the chief of defence, General Eirik Kristoffersen, said.

The scale of alert on which the military operates is classified, however, and the government declined to give details of the level.

There were no concrete threats against Norway now triggering the decision, Kristoffersen told Reuters, but rather the sum of "the uncertainties" was leading authorities to raise the country's military preparedness.

"We have seen an escalation (in the war) in Ukraine, we (Norway) are training Ukrainian forces, the Ukraine war has changed with the Russian mobilisation," he said an interview.

"And at the same time, we have had a gas explosion in the Baltic Sea and drone activity at North Sea platforms."

The raised level is expected to last a year, "possibly more", Kristoffersen added.