"Currently we are not planning to increase our military presence in the region, but what we are planning is to strengthen our ability to reinforce if needed," Stoltenberg told reporters after talks with Dutch Prime Minister Mark Rutte.

The leaders of Baltic states, Estonia, Latvia and Lithuania, occupied and annexed by the Soviet Union during World War II, are seeking extra US aid to ward off any Russian moves against them.

They are urging the United States to send more troops and bolster air defences on NATO's eastern flank.

Last year, NATO deployed four multinational battalions to Poland and the Baltic states as tripwires against possible Russian adventurism, while the US military sent a Patriot battery to Lithuania for drills.

"If there is a need, we need to have ready forces which can deploy very quickly," Stoltenberg added.

The issue is set to be discussed at the next NATO summit in July in Brussels, he added.

Since the fall of the Soviet Union, the Baltic countries have turned away from Moscow's orbit by joining NATO's mutual defence pact and the European Union.

Russian President Vladimir Putin has never made any secret of the fact that he resents this and regards former Soviet republics as belonging in Moscow's zone of influence.