UPDATE 1-U.S. and Russia trade accusations over 'visa war' as ties fray

* U.S. and Russia at odds over visas for teachers

* Issue affects Moscow school for diplomats' children

* Moscow blames Washington for visa row (Recasts to add Russian foreign ministry statement)

By Tom Balmforth and Andrew Osborn

MOSCOW, July 17 (Reuters) - The United States and Russia on Wednesday accused each other of using children as political hostages after dozens of teachers at an English-language school in Moscow patronised by the children of Western diplomats were left without visas.

U.S. Ambassador Jon Huntsman said 30 teachers who had been due to arrive in Moscow next month had not been able to get visas, a move that he said could force the Anglo-American School of Moscow to scale back the number of children attending.

"Children should not be used as pawns in diplomatic disputes," Huntsman said in comments shared by the U.S. embassy. He said he hoped to resolve the issue before the school year starts.

But Moscow blamed Washington for the dispute, saying it had been forced to retaliate against U.S. treatment of its own diplomats and embassy teachers in the United States.

Maria Zakharova, a foreign ministry spokeswoman, accused Washington of starting a visa war two years ago that had made it hard for Moscow to rotate its diplomats through the United States.

She also said that Washington expected Russia to issue diplomatic visas for the teachers in Moscow, even though it was unwilling to issue the same kind of visas for Russian teachers who work in a school on the grounds of the Russian embassy in Washington.

Russia was ready to issue the teachers with visas as soon as the United States did the same for Russian diplomatic personnel, she added, calling children at the Moscow school "hostages of American diplomacy".

Originally founded by the U.S., British and Canadian embassies in 1949 for the children of diplomats, the Anglo-American School is now attended by 1,200 students, including children of embassy staff, other expatriates and wealthy Russians.

Russia's Ministry of Foreign Affairs informed the U.S. embassy in Moscow last week that it would not issue visas for the incoming teachers, according to a letter sent to parents by Heather Byrnes, a U.S. diplomat.

The letter warned parents of "serious consequences" for the school, potentially forcing it to reduce enrolment.

Russia's Kommersant newspaper reported in June 2017 that Moscow was considering making life difficult for the school to retaliate against punitive measures that former U.S. President Barack Obama took against Russia in 2016.

Western relations with Moscow have been strained since 2014, when the United States and the European Union imposed sanctions over Russia's seizure of territory from Ukraine and its support for separatists there. Other issues causing friction range from Syria to the poisoning of a former Russian spy in England. (Editing by Peter Graff and Frances Kerry)