(Adds Belarus saying Russia to send warplanes)
By Andrei Makhovsky
MINSK, March 12 (Reuters) - Russia will send several warplanes to its military ally Belarus in response to increased NATO activity near the borders of the ex-Soviet republic, the commander of the Belarussian air force was quoted as saying on Wednesday.
President Alexander Lukashenko had said earlier that Belarus would ask Russia to deploy 12 to 15 warplanes on its territory after the United States and Poland began war games that are expected to involve at least 12 U.S. F-16 fighter jets.
Belarus borders Russia, Ukraine and NATO members Poland, Lithuania and Latvia. Further south, a joint exercise of U.S., Bulgarian and Romanian naval forces in the Black Sea started on Wednesday.
The drills were planned before the crisis in Ukraine but underscore support for NATO nations near Russia, which has taken control of Ukraine's Crimea region and has warned it could invade to protect Russians there after the president was ousted.
"We reacted calmly until large-scale exercises began ... in Poland," Lukashenko said. "There is a clear escalation of the situation near our borders."
He said Belarus would ask Russia to send "no more than 12 to 15 planes", indicating that the request had been made under a clause of a "union treaty" signed by the two Slavic nations after the Soviet Union's collapse.
"Send them to Belarus, determine their patrol routes," Lukashenko said. "Let them work, let them patrol."
Belarus air force commander Oleg Dvigalev later said Russia had agreed to move an unspecified number of fighter jets to Belarussian airfields, the state news agency Belta reported.
The Russian Defence Ministry could not immediately be reached for comment. Russia normally has a handful of Sukhoi fighter jets stationed at a Belarussian base.
Belarus serves as a buffer between Russia and NATO and is one of Moscow's closest allies. Lukashenko relies on political and economic support from Moscow, but relations are often tense and he has said little about the crisis in Ukraine.
Russia uses a Soviet-era early-warning radar station in Belarus and has supplied its neighbour with weapons including air defence missile batteries. The two nations have been in talks about putting a Russian air base in Belarus. (Writing by Steve Gutterman; Editing by Alison Williams)