Islamic State's official magazine carried a photo on Wednesday of a Schweppes drink it said was used to make an improvised bomb that brought down a Russian airliner over Egypt's Sinai Peninsula last month, killing all 224 people on board.

The photo showed a can of Schweppes Gold soft drink and what appeared to be a detonator and switch on a blue background, three simple components that if genuine are likely to cause concern for airline safety officials worldwide.

"The divided Crusaders of the East and West thought themselves safe in their jets as they cowardly bombarded the Muslims of the Caliphate," the English language Dabiq magazine said in reference to Russia and the West. "And so revenge was exacted upon those who felt safe in the cockpits."

Western governments have said the plane was likely brought down by a bomb and Moscow confirmed on Tuesday it had reached the same conclusion, but the Egyptian government said it has still not found evidence of criminal action.

State Department spokesman John Kirby said on Wednesday the US government was not in a position to confirm "the veracity" of the magazine's claim.

"We do believe that terrorist activity is likely the reason," he said, referring to the crash.

He added that the United States had no reason to doubt the group's claim of responsibility.

The United States had previously said it could not rule out the possibility that terrorism had caused the plane crash.

Islamic State also published a photo of what it said were passports belonging to dead Russians "obtained by the mujahideen". It was not immediately possible to verify the authenticity of the published photos.

The group, which has seized large swathes of Syria and Iraq, said it had exploited a loophole at Sharm al-Sheikh airport, where the plane originated, in order to smuggle a bomb on board.

The airport is widely used by budget and charter airlines to fly tourists to the nearby resorts on the Sinai coast.

Islamic State said it had initially planned to bring down a plane belonging to a country participating in the US-led coalition bombing it in Syria and Iraq, but it changed course after Moscow started its own air strikes campaign in Syria.

"A bomb was smuggled onto the airplane, leading to the deaths of 219 Russians and five other crusaders only a month after Russia's thoughtless decision," it said.

Egypt's interior minister told a news conference in Sharm al-Sheikh on Tuesday that there was "no information" about security lapses at the airport.

Islamic State's Egyptian branch, Sinai Province, claimed responsibility for the attack the day it happened but Egyptian officials were quick to dismiss talk of a bomb as premature.

NO SAFETY IN MUSLIM LANDS

Egypt is battling an Islamist insurgency in the Sinai, a strategic peninsula bordering Israel, Gaza and the Suez Canal. But Islamic State said the airline attack was primarily planned as a response to Russian and Western air strikes.

"This was to show the Russians and whoever allies with them that they will have no safety in the lands and airspace of the Muslims," the group wrote. "That their daily killing of dozens in (Syria) through their air strikes will only bring them calamities."

Russia, an ally of Syrian President Bashar al-Assad, launched air strikes against opposition groups in Syria including Islamic State, on Sept. 30.

Since the attacks on Paris, both Russia and France have stepped up the tempo of air strikes.

The downed aircraft, an Airbus A321 operated by Metrojet, had been carrying Russian holidaymakers from the Egyptian resort to St Petersburg when it broke up over Sinai.

On Tuesday, Russian President Vladimir Putin vowed to hunt down those responsible for blowing up the plane and offered a $50 million reward for information leading to those responsible.

"We will find them anywhere on the planet and punish them," Putin said of the plane bombers at a sombre Kremlin meeting.

Alexander Bortnikov, the head of Russia's FSB security service, said traces of foreign-made explosive had been found on fragments of the downed plane and on passengers' personal belongings. He said the bomb probably contained around 1 kg (2.2 pounds) of TNT.

Egypt has not officially given a reason as to why the plane was brought down, calling on all sides to await the official results of an investigation carried out by an Egyptian-led team.

The government said it would "take into consideration" Russia's findings but that it was yet to find any evidence of criminal action bringing down the plane. – Reuters