MOSCOW (Reuters – A Russian Aeroflot plane flying between Tel Aviv and Moscow had to alter its altitude due to a NATO CL-600 reconnaissance aircraft crossing the designated path. This was according to Russia’s State Aviation Authority.

After being told by air traffic control that an aircraft was in its way, the flight SU501, carrying 142 passengers, had to land at 2,000 feet.

It was possible to see another plane as they flew by the sky.

Rosaviatsia (aviation authority) stated that a CL-650 smaller aircraft, flying from Sochi, Black Sea, to Skopje, had also to alter its course.

The NATO country the reconnaissance aircraft was belonging to wasn’t mentioned. Russia’s Defence Ministry stated that it had sent fighter jets in order to transport two U.S. military reconnaissance aircrafts across the Black Sea.

At the time the Interfax news agency reported it, the U.S. Embassy Moscow had no comment.

Rosaviatsia stated that an increase of NATO planes flying in the area was posing risks to civilian aircrafts, and that Moscow would lodge a diplomatic complaint.

The international tensions over Ukraine have been increasing.

NATO countries and Kyiv allege Russia that it has built up troops in Ukraine. This raises fears about an attack. Moscow says there’s no such plan. It accuses Kyiv that it has built up forces in its eastern region, where Russian-backed separatists have a significant portion of the territory.