Two Russian military aircraft recently flew under an Icelandic passenger jet without their transponders activated, raising queries about risky behaviour, an Icelandic daily said Monday.
The two Tu-22M bombers were observed Thursday in international airspace off Iceland as they approached and passed under an Icelandic passenger plane en route to Sweden, Morgunbladid reported.
Since the transponders were switched off, the bombers were invisible to civilian radar.
Similar encounters between military and civilian planes have been reported - and criticized - in recent years in the Baltic Sea region as Russia has increased its military flights in northern Europe.
Air traffic controllers in Reykjavik said the Russian planes had switched off their transponders and did not notify them as they approached the passenger aircraft, the report said.
The passenger jet's captain said he spotted the planes from the cockpit and labelled the behaviour as risky.
A Russian diplomat in Reykjavik, Alexey Shadskiy, was quoted as saying the planes flew in accordance with international rules, and were about 2 kilometres below the passenger plane's flight path.
He suggested the report was aimed at "reviving fear" of Russia and was part of an argument to re-open the Keflavik airbase that the United States, Iceland's NATO ally, closed in 2006.
Shadskiy noted that NATO planes at times also flew without their transponders activated.
According to the daily, the bombers were observed "near Spain" before they returned back to Russia.