Aeroflot's ability to sell seats has been crippled by Sabre.

The reservation system that is the core of airlines around the world has stopped working because of a dispute with Aeroflot.

Sean Menke, the CEO of Sabre, said on Thursday that the company is taking a stand against the military conflict.

Aeroflot's flights won't show up on online travel agencies or other third-party sites because of the software giant's decision to end the distribution agreement.

We will not sign any new contracts in Russia, and we will evaluate our existing portfolio of work in Russia in parallel.

We continue to assess and evaluate the impact of international sanctions imposed on Russia and any counter-measures by Russia.

Aeroflot has yet to comment on the announcement.

After most of the western world closed their airspace to Russian planes, the move is the latest significant measure against Russia's aviation industry.

Boeing, General Electric and Airbus suspended support services to Russian airlines.

Russian airlines are expected to take over leased planes to keep others flying.

The Russian Transport Ministry said it might try to use three planes to run one, meaning it would save two planes for spare parts to keep one flying on average.

The ministry said that it could keep Russian planes flying for more than six months.