WASHINGTON (AFP) - The United States will spend US$3.4 billion (S$4.85 billion) next year to counter "Russia's aggression" and boost the US presence in eastern European nations, Defence Secretary Ashton Carter said on Tuesday (Feb 2). It will also spend US$7.5 billion (S$10.7 billion) to fund the fight against the Islamic State in Iraq and Syria (ISIS).

"We're reinforcing our posture in Europe to support our Nato allies in the face of Russia's aggression," Mr Carter said, noting that the US$3.4 billion was a quadrupling of funds from last year.

"That'll fund a lot of things. More rotational US forces in Europe, more training and exercises with our allies, more prepositioned warfighting gear, and infrastructure improvements to support it."

The US also will spend US$7.5 billion - a 50 per cent increase - to fund the fight against ISIS, Mr Carter said.

"Because we are accelerating the campaign, (the Pentagon) is backing that up in our budget with a total of US$7.5 billion dollars in 2017, 50 per cent more than 2016," he said in a speech in Washington.

"This will be critical as our updated coalition military campaign plan takes hold."