Moscow, May 17 (IANS/RIA Novosti): Russia will deliver 12 Mil Mi-17V5 military transport helicopters to the Afghanistan Armed Forces by the end of 2013, Russian state arms exporter Rosoboronexport said.

The helicopters were options in a $367.5 million deal Rosoboronexport signed with the Pentagon in May 2011 for delivery of 21 Mi-17V5s.

According to US officials, the deal could be worth up to $900 million including spares and servicing.

"The option agreement has been signed and the delivery will be completed by the end of this year," said Grigory Kozlov, director of Rosobornexport's helicopter exports department.

Koslov said the Pentagon has already started paying for the option deal as well as delivering US equipment to be installed on Russian helicopters specifically for Afghan missions.

Russia and the US may soon start new negotiations on the purchase of additional Mi-17 helicopters for Afghanistan despite opposition from some US lawmakers, Kozlov said.

"I think this issue (the additional purchase) will be decided by the end of May and we will enter a new round of talks on the delivery of helicopters on top of the current 21 plus 12 units," Kozlov said.

The deal to provide Russian helicopters for Afghanistan's armed forces, paid for by the US, has attracted considerable criticism from some politicians there.

The US Department of Defense said in April it plans to sidestep a Congressional ban to purchase helicopters from Rosoboronexport, despite objections from US lawmakers who allege that the firm has equipped the Syrian government with equipment, including helicopters, to attack civilians.

The Afghanistan armed forces want Russian-made helicopters in preference to others, because they have a history of using them since the Soviet invasion, and because of their low prices, durability and simplicity.