Britain’s foreign minister said Monday it is highly likely that a bomb planted by a supporter of ISIL Takfiri group downed the Russian passenger jet crashed over Egypt.

Britain's foreign minister said Monday it is highly likely that a bomb planted by a supporter of the Takfiri group, ISIL (so-called Islamic State in Iraq and Levant) downed the Russian passenger jet crashed over Egypt.

"We think it was more likely than not an explosive device on the aircraft," Philip Hammond said of the cause of the October 31 crash, which killed all 224 people on board a Russia-bound flight leaving the resort of Sharm el-Sheikh.

"There's got to be a high probability that ISIS was involved," he added, speaking to CNN and using an alternative acronym for the ISIL.

"That doesn't mean that it was a directed attack from ISIS headquarters in Syria," Hammond added, shortly before he was due to attend talks in Washington with US Secretary of State John Kerry.

"It may have been an individual who was inspired by ISIS who was self-radicalized by looking at ISIS propaganda and was acting in the name of ISIS without necessarily being directed."

Asked specifically by CNN whether there was a "high probability" that the attack was caused by a bomb planted by the ISIL group, Hammond said: "That's the way it looks at the moment."