A woman places flowers in front of the portraits of crew members of the crashed Airbus A321 plane, operated by Russian airline Kogalymavia, in the company's office in Moscow, Russia November 2, 2015. [Photo/Agencies]

When asked if a terrorist attack could be to blame, Putin's spokesman Dmitry Peskov said no theory could yet be ruled out.

Alexander Smirnov, deputy general director of airline Kogalymavia, which operated the plane under the brand name Metrojet, said only a "technical or physical action" could have caused the aircraft to break up in the air.

"The plane was in excellent condition," Smirnov told a news conference in Moscow. "We rule out a technical fault and any mistake by the crew."

Kogalymavia's deputy general director for engineering, Andrei Averyanov, said a 2001 incident when the plane's tail section struck the tarmac on landing was fully repaired and could not have been a factor in the crash.

The airline said the plane's engines were inspected in Moscow on Oct 26 and no problems were found and a Russian inspection of its fuel found that it met requirements.

The aircraft had received a certificate of airworthiness earlier this year from regulators in Ireland.