Iran will receive the bulk of the S-300 air defense missile systems it ordered from Russia by the end of the year, Tehran’s defense minister said Wednesday, according to the AFP news agency.

“We signed a contract with Russia. It is being done. We will acquire a large portion of the systems by the end of this year,” Iranian Minister of Defense Hossein Dehghan was quoted as having said.

He said Iranian troops were being trained in Russia to operate the surface-to-air missile systems.

The announcement came two days after Russia’s state-run Russian Technologies corporation (Rostec) announced the signing of a delivery contract for S-300 missiles with Iran.

The S-300 is a long range surface-to-air missile – manufactured by the Russian firm Almaz – designed to intercept aircraft and cruise missiles, and its most advanced models can also target ballistic missiles.

The sale of the S-300, originally conducted in 2007, has been repeatedly delayed due to Western pressure given that UN nuclear sanctions ban the delivery to Iran.

But in April, Russian President Vladimir Putin signed a decree lifting a ban on the delivery of the S-300 systems to Iran, explaining that his decision was motivated by Iran’s drive to find a solution in talks over its nuclear program.

In August Russia’s deputy foreign minister Mikhail Bogdanov said his country and Iran had formally reached a deal for Moscow to deliver Tehran advanced S-300 missile systems, although the announcement has never materialized.