MOSCOW (Reuters) - Russia's national flag carrier Aeroflot is planning to add nine medium-haul A320 Neo Airbus planes for about $870 million (£692 million) to its fleet next year, procurement documents show.

The plan includes leasing six Airbus A320-251N for 12 years - the bidding process for which was launched on Monday - and three A321-251NX jets.

Aeroflot has 367 aircraft in its fleet, including 248 medium-haul A320 and Boeing 737 jets. It currently has no new generation A320 Neo.

Russia's national carrier has announced plans to increase its fleet to 520 jets by 2023, including with an order of 100 Russian-made regional Sukhoi Superjet aircraft and medium-haul MS-21 planes.

The airline has not expressed any desire to order Boeing 737 Max aircrafts, which were grounded worldwide in March after a second crash.

But Aeroflot's low-cost subsidiary Pobeda is awaiting its first Boeing 737 Max in November this year. Boeing 737 is the main competitor of the A320 family.

(Reporting by Gleb Stolyarov; editing by Deepa Babington)