0930 GMT March 25, 2019
British Prime Minister David Cameron said on Thursday it was increasingly likely a bomb brought down the Russian airliner, and US President Barack Obama said Washington was taking that possibility "very seriously", Reuters reported.
But Moscow said it was premature to reach conclusions that the flight was attacked.
In a telephone call, Russian President Vladimir Putin told Cameron it was important that assessments of the cause of the crash last Saturday be based on information from the official investigation, Interfax news agency reported.
Egypt, which depends on tourism as a crucial source of revenue, said there was no evidence a bomb was to blame.
A Sinai-based group affiliated with ISIL group, the terrorist group that has seized swathes of Iraq and Syria, has claimed responsibility for the crash, which if confirmed would make it the first attack on civil aviation by the world's most violent organization.
Cameron, who hosted Egyptian President Abdul Fattah al-Sisi on Thursday for a previously scheduled visit, said: "We cannot be certain that the Russian airliner was brought down by a terrorist bomb, but it looks increasingly likely that was the case."
His foreign secretary, Philip Hammond, said it was "a significant possibility" that ISIL was responsible, given a range of information, including the claim of responsibility.
Dmitry Peskov, a spokesman for President Vladimir Putin, was reacting to an assertion from British Foreign Secretary Philip Hammond who said that there was a significant possibility that ISIL's Egyptian affiliate had orchestrated a bomb attack on the Russian airliner.
Bomb on board
In his first public comments on the disaster, Obama said in a radio interview: "There's a possibility that there was a bomb on board. And we're taking that very seriously."
"We're going to spend a lot of time just making sure our own investigators and own intelligence community find out what's going on before we make any definitive pronouncements. But it's certainly possible that there was a bomb on board," Obama told KIRO/CBS News Radio in Seattle.
On Friday, Russian president agreed that all flights over Sinai Peninsula should be suspended during the A321 crash investigation.
Vladimir Putin agrees with Federal Security Service (FSB) Alexander Bortnikov's recommendation to suspend passenger flights to Egypt while the investigation of the Sinai plane crash is underway, Kremlin spokesman said.
"The head of state agreed with these recommendations. Putin instructed the government to work out mechanisms for the implementation of these FSB recommendations, and to ensure the return of Russian citizens," Peskov told reporters.
Britain, Ireland, Germany and the Netherlands have suspended flights to and from Sharm El-Sheikh, leaving thousands of European tourists stranded in the Red Sea resort where the plane took off.
Russia, an ally of Syrian government, launched air raids against terrorist groups in Syria including ISIL terrorist group on September 30.
ISIL has waged a bloody campaign of bombings and shootings in recent months.