Russian intelligence has confirmed that it was a bomb detonated in flight that brought down a Russian Metrojet in the Sinai desert a few weeks ago, killing all 224 people on board. Russian intelligence said that trace amounts of an explosive were uncovered in the wreckage of the plane.

Western intelligence sources have suspected that a bomb was the cause of the crash, but this is the first and only time it has been officially declared by the Russians, according to The Washington Post. Russian officials have now said the crash the work of terrorists.

The Metrojet had left the Sinai desert resort city of Sharm el-Sheikh bound for Saint Petersburg, Russia, when the explosion occurred in midair, killing everyone on board. Egyptian authorities have reported that they have detained a pair of suspects who were apprehended at the airport in Sharm el-Sheikh. Egyptian authorities believe the two  suspects were involved in the operation, and have arrested 17 people in all in connection with the crash of the plane.

Vladimir Putin stood at a press conference with his chief of the Russian intelligence service on Tuesday and vowed that the murderers would be brought before Russian justice. Putin vowed to search for them everywhere and that there would be no place they could hide. In addition, Russia has offered a $50 million reward for any information leading to the capture of those responsible.

While the Islamic State was not mentioned specifically by Putin, he did order his air force in Syria to increase their air attacks on Islamic State targets there. Western leaders, including U. S. President Barack Obama, have been wary about declaring it a bomb. They say there is evidence to support that but they don’t find it conclusive as of yet.

Putin also warned other countries of the world. He announced that any country that might be giving the perpetrators safe harbor would feel the wrath of Russian vengeance.