A Russian charter flight ferrying 224 passengers and crew to St. Petersburg from the Red Sea resort of Sharm el-Sheikh crashed soon after taking off early Saturday, killing everyone onboard, officials in Egypt and Russia said.

New York Times reports that the plane, an 18-year-old Airbus A321, disappeared from radar screens about 25 minutes after it took off from the Egyptian resort, according to official accounts. The pilot had radioed that he had technical problems and needed to make an emergency landing, press reports in Egypt quoted officials there as saying.

The plane had apparently been trying to land at the airport at Al-Arish, in northern Sinai, when it crashed in the Hasana region, a mountainous area south of the city.

Hours after the crash, a branch of the Islamic State operating in the Sinai Peninsula issued a claim of responsibility. There has been a violent insurgency for several years against the Egyptian government in Sinai, but there has been no indication that the terrorist organization there possesses the weapons needed to bring down a plane from a high altitude.

Maxim Sokolov, the Russian minister of transportation, issued a statement rejecting reports that the plane had been shot down.

“This information cannot be considered credible,” Mr. Sokolov said. “We are in a close contact with our Egyptian colleagues, with the aviation authorities of this country. At the moment they have no information that would confirm such fabrications.”

The plane was flying at 31,000 feet when it began to descend, and the general range of the shoulder-fired missiles commonly known as Manpads that have been used against Egyptian military helicopters in the region is much lower, around 20,000 feet.

Speaking on a nationally broadcast news conference, Mr. Sokolov said the cause of the crash had yet to be confirmed. Russian news reports said that preliminary details gave no indication that the plane was shot down.

Asked about a possible link to terrorism and warnings not to fly over that region due to the insurgency there, Mr. Sokolov said the Egyptian government had not closed the airspace over the Sinai Peninsula.

Egyptian military aircraft spotted the wreckage of the plane in a mountainous area in Sinai, according to a government statement. All on board the plane had been killed, the Russian Embassy in Cairo said in a brief statement on Twitter.

Press reports in Egypt quoted the initial security services who reached the site as saying the plane had broken in two, with many of the passengers still strapped in their seats. The Egyptian government dispatched about 50 ambulances to collect the remains of the passengers.

The Egyptian statement said that the plane had been carrying 217 passengers, including 17 children, and seven crew members. Everyone onboard was Russian, most from the St. Petersburg region, except for three passengers from Ukraine and one from Belarus.

The plane left the airport in the resort city shortly before 6 a.m. and disappeared from radar screens at 6:20 a.m.

A website called Flightradar24, which tracks air traffic around the globe, said the plane had been descending at a rate of 6,000 feet per minute just before it disappeared from radar. Eyewitnesses reported one engine on fire as it went down, according to a report in Masry Al-Youm, an Egyptian newspaper.

In St. Petersburg, friends and relatives who showed up at Pulkovo airport to meet the flight were shuttled to the nearby Crowne Plaza hotel. They remained cordoned off in a corner of the lobby, awaiting developments. A Russian Orthodox priest and at least one grief counselor circled among them.

Occasionally one of those waiting would wander through the lobby, shedding tears, but they declined to address reporters.

Vladimir V. Putin, the president of Russia, ordered the establishment of a state commission to investigate the crash. The Russian government also announced it was dispatching a plane from its emergency services to take a team of investigators and rescuers to the scene.

Mr. Putin also declared Sunday a day of mourning for the victims, and all entertainment programs on Russian television were canceled. It was the deadliest accident in Russian aviation history, press reports in Russia said.

A criminal investigation was opened, although there was no immediate announcement of any specific accusations.

The plane was operated by Kogalymavia, which is privately owned, and flies airplanes under the name Metrojet. Some Russians who have flown the airline took to Twitter to complain about the condition of the airplanes, with one saying a window was held in place with duct tape and another saying that on a recent flight to Turkey his seat had no seatbelt. Those claims were not immediately verifiable.

There was nothing remarkable about the airline’s safety record, though the fuel tank on one of its planes exploded before departure from the Siberian city of Surgut in 2011, and the ensuing blaze killed three people.

The airline issued a statement saying that there had been no human error attributable to the experienced pilots. The plane was in good mechanical order, it said.