Update: UAE airlines Emirates, Air Arabia and Flydubai said on Sunday they were re-routing flights to avoid Egypt's Sinai Peninsula, where a Russian aircraft carrying 224 passengers crashed on Saturday.
The airlines said they were closely monitoring the area and the re-routing was a security precaution, according to separate emailed statements to Reuters. Re-routing usually means longer flying distances, which add to fuel costs.
Budget carrier easyJet said it was taking advice from all relevant authorities and was continuing to "actively review" the situation. British Airways said in a statement that it did not discuss flight routes, "however we would never fly a route unless it was safe to do so".
EasyJet said that it, like other British airlines, did not overfly central and northern Sinai on the advice of Britain's Department of Transport. The Russian plane crashed into a mountainous area of central Sinai on Saturday.
"Based on the information received to date, easyJet plans to continue to operate flights to Egypt to carry holidaymakers as planned to and from Sharm el-Sheikh and Hurghada but will continue to actively review the situation," it said in a statement.
On Saturday, German carrier Lufthansa and Air France-KLM said they had decided to avoid flying over the peninsula while they waited for clarity on what caused the crash.
A militant group affiliated to Daesh in Egypt, Sinai Province, said in a statement it had brought down the plane "in response to Russian air strikes that killed hundreds of Muslims on Syrian land", but Russia's Transport Minister told Interfax news agency the claim "can't be considered accurate".
All 224 dead
A Russian airliner crashed in Egypt's Sinai Peninsula on Saturday, killing all 224 people on board, with officials launching a probe but swiftly downplaying a claim of responsibility by Daesh militants.
The Daesh affiliate in Egypt said it was behind the crash of the flight run by the Kogalymavia airline, which operates under the name Metrojet, but did not give details and Cairo and Moscow both cast doubt on the claim.
Egyptian Prime Minister Sharif Ismail said experts had confirmed that a plane cannot be downed at the altitude the Airbus 321 was at, while Russian Transport Minister Maxim Sokolov said the claim "cannot be considered accurate".
Germany's Lufthansa, Emirates and Air France said they would halt flights over Sinai until the reasons behind the crash became clear.
In March, the US Federal Aviation Administration had advised US civil aircraft to avoid flight operations in the Sinai Peninsula below 26,000 feet.
The plane, carrying 214 Russian and three Ukranian passengers and seven crew, lost contact with air traffic control 23 minutes after taking off from the Red Sea resort of Sharm el-Sheikh, bound for Saint Petersburg.
"Unfortunately, all passengers of Kogalymavia flight 9268 Sharm el-Sheikh-Saint Petersburg have died. We issue condolences to family and friends," the Russian embassy in Cairo said.
Wreckage and dead bodies were found scattered over an area of six to eight square kilometres (two-and-a-half to three square miles), around 100 km (60 miles) south of the town of El-Arish, Egyptian officials said.
In this photo taken on Tuesday, Oct. 20, 2015, The Russian airline Kogalymavia’s Airbus A321 with a tail number of EI-ETJ on an airstrip of Moscow’s Domodedovo international airport, outside Moscow, Russia. Russia's civil air agency is expected to have a news conference shortly to talk about the Russian Metrojet passenger plane EI-ETJ, that Egyptian authorities say has crashed in Egypt's Sinai peninsula. (AP)
The plane's black box data recorders have been recovered and sent for analysis, Ismail said. Late Saturday Russian Transport Minister Sokolov and Emergencies Minister Vladimir Puchkov arrived in Cairo with a team of experts to take part in an Egyptian-led investigation.
Two air accident investigators from France -- Airbus's home country -- are also to travel to Egypt along with six experts from the aerospace giant to help with the probe.
The Daesh affiliate waging an insurgency in the Sinai claimed that "the soldiers of the caliphate succeeded in bringing down a Russian plane", saying it was revenge for Russian air strikes against Daesh in Syria.
The charter flight was at 30,000 feet when communication was lost, according to an Egyptian official, and three military experts said Daesh in Sinai does not have surface-to-air missiles capable of hitting a plane at high altitude.
But they could not exclude the possibility of a bomb on board or a surface-to-air missile strike if the aircraft had been descending.
After not answering its phones for much of the day, Kogalymavia broke its silence with a statement offering condolences to the families of the victims. "We will all need great courage to overcome these losses," it said.
It defended the pilot, saying he had "more than 12,000 hours" of flight experience, "including 3,860 hours with Airbus A321".
Russia has declared Sunday a day of national mourning for the victims, who ranged in age from a 10-month-old girl to a 77-year-old woman.
At Saint Petersburg's Pulkovo airport, family members faced an anxious wait for news.
Ella Smirnova, 25, said she had come to meet her parents.
"I will keep hoping until the end that they are alive, but perhaps I will never see them again," she said.
Relatives react at Pulkovo international airport outside Saint Petersburg after a Russian plane with 224 people on board crashed in a mountainous part of Egypt's Sinai Peninsula on October 31, 2015. Ambulances reached the site and began evacuating "casualties," officials and state media reported, without elaborating on their condition. The plane took off early in the morning from the southern Sinai resort of Sharm el-Sheikh bound for Saint Petersburg in Russia but communication was lost 23 minutes after departure, officials said. (AFP)
An Egyptian air traffic control official said the pilot told him in their last exchange that he had radio trouble, but Civil Aviation Minister Mohamed Hossam Kamal later told reporters that before the crash communications had been "normal".
"There was nothing abnormal... and the pilot didn't ask to change the plane's route," he said. Russian aviation official Sergei Izvolsky told Interfax news agency the aircraft took off from Sharm el-Sheikh at 5:51 am (0351 GMT) and 23 minutes later failed to make contact with air traffic control in Cyprus.
Russia has a dismal air safety record, with charter operators often under pressure to book to capacity on ageing jets in an attempt to cut costs.
Kogalymavia is a small carrier that flies mostly international charter services.
The crash is likely to raise renewed concerns about the safety of air travel in a country with an ageing fleet.
The last major air crash in Egypt was in 2004, when a Flash Airlines Boeing 737 plunged into the Red Sea after taking off from Sharm el-Sheikh.
All 148 people on board, most of them French, died.
Millions of tourists, including many Russians, visit the resort, one of Egypt's major attractions famed for its pristine beaches and scuba diving.