Russia is assembling S-300 anti-aircraft defense systems to start shipments to Iran by next year, the Kremlin’s top official for the arms trade said.

Russia is also modernizing some parts of the systems and revising contract terms, including the pricing, Vladimir Kozhin, President Vladimir Putin’s aide on military-technical cooperation, said in an interview on Tuesday.

Putin ended a self-imposed embargo on supply of the S-300 in April after five years, prompting objections from the U.S. and Israel. The Russian leader said at the time that the transfer would help create a balance in the region. Iran said it expects to take delivery this year. […]