By Jonathan Landay

WASHINGTON (Reuters) - Russia is moving nuclear-capable missiles into Kaliningrad, a tiny Russian enclave sitting between Poland and Lithuania, a U.S. intelligence official said Friday, confirming Estonian news reports.

Russia's reasons for shipping the 500-kilometer-range Iskander-M missiles to Kaliningrad "could be innocuous," said the official, who spoke on condition of anonymity.

"They moved a similar missile system to Kaliningrad in 2014 for a military exercise. It could also be a political gesture - a show of strength - to express displeasure with NATO," said the official.

(Reporting by Jonathan Landay; Editing by James Dalgleish)