By Andrea Shalal

ABOARD USS HARRY S. TRUMAN (Reuters) - The U.S. military will have two aircraft carriers in the Mediterranean Sea this month ahead of a NATO summit in Warsaw as Washington seeks to balance Russian military activities and accelerate its fight against Islamic State militants.

The USS Harry S. Truman aircraft carrier will hand off to the USS Dwight D. Eisenhower when it arrives en route to the Gulf, allowing the Truman to head back to the United States after an extended eight-month deployment, Navy officials on board the Truman said.

The United States European Command later issued a statement confirming that the Dwight D. Eisenhower Carrier Strike Group had entered the Mediterranean Sea on Wednesday "in support of U.S. national security interests in Europe".

The move coincides with NATO military exercises across eastern Europe and Turkey that may raise tensions with Russia. U.S. officials say Russia is operating warships and submarines in the Mediterranean and plans its own exercises in coming weeks.

Kremlin spokesman Dmitry Peskov said on Tuesday the NATO exercises did not contribute to an atmosphere of trust and security.

Captain Ryan Scholl, commanding officer of the Truman, said there had been no interactions with Russian warships and U.S. and Russian pilots were largely abiding by the rules of engagement for air operations aimed at avoiding the potential for miscalculation.

"The extension of Truman and movement into the European Command theater, plus the overlap with the Eisenhower Carrier Strike Group, enables the continued degradation of ISIL and a host of operational benefits," said Captain Danny Hernandez, spokesman for U.S. European Command, referring to the Islamic State militant group.

He said the overlapping carrier deployments were also intended to enable missions such as Operation Atlantic Resolve, aimed at reassuring U.S. allies in Europe after Russia's annexation of Crimea.

The Truman has used the 72 warplanes on board to drop 1,481 smart bombs and pamphlets on Islamic State targets in Iraq and Syria since last December when it arrived in the Gulf, the Navy said on Wednesday.

It said jets based on the Truman had launched 68 raids over Iraq and Syria and delivered 52 precision weapons since moving to the Mediterranean from the Gulf last Friday.

Islamic State has lost 45 percent of its territory in Iraq and its oil revenues have been halved in Syria, said Rear Admiral Bret Batchelder, commander of the Truman strike group.

(Additional reporting by Michael Nienaber in Berlin; Editing by Janet Lawrence/Mark Heinrich)