Spotlight: World leaders extend condolences over Russian plane crash in Egypt

World leaders have expressed sincere condolences over the crash of a Russian airliner in Egypt on Saturday which killed all the 224 people onboard.

Chinese President Xi Jinping sent a message of condolences on Sunday to his Russian counterpart Vladimir Putin, extending profound condolences to the victims of the crash and expressed sincere sympathies to the families of the victims.

At the current sorrowful moment for the Russian people, the Chinese people firmly stand side by side with them, Xi said.

Chinese Premier Li Keqiang, who was in Seoul, South Korea to attend the sixth China-Japan-South Korea leaders' meeting, also sent a message of condolences on Sunday to his Russian counterpart Dmitry Medvedev.

U.S. Secretary of State John Kerry on Saturday extended the "deepest condolences" to Russia over the tragic plane crash, a U.S. State Department statement said.

While speaking to Russian Foreign Minister Sergey Lavrov "to express deepest condolences to the families and friends of those killed in the crash in Egypt of Kogalymavia Flight 9268," Kerry also offered to provide U.S. assistance, if needed, it added.

European Commission President Jean-Claude Juncker on Saturday also expressed condolences over the Sinai plane crash, saying the European Union stands with the Russian people and with the families of the victims.

"I was saddened to learn about the loss of so many lives in the plane crash over Sinai earlier today," Juncker said in a statement, stressing that "the relevant European authorities are ready to provide any necessary assistance in the investigations following this tragedy."

Canada's Prime Minister-designate Justin Trudeau Saturday expressed in a statement his condolences to the families and friends of victims of the crashed Russian passenger plane in Egypt.

"While we do not yet know the cause of this terrible crash, I extend my deepest condolences to the families and friends of all those who lost their lives in today's tragedy," said the Canadian prime minister-designate, who is to swear in next Wednesday in Ottawa after his Liberal Party defeated the ruling Conservative Party led by Prime Minister Harper on October 19 this year.

The Airbus A-321 operated by Russian airline Kogalymavia, with 217 Russian passengers and seven crew members onboard, crashed early Saturday in the Sinai Peninsula shortly after it took off from Egypt's Red Sea Resort Sharm el-Sheikh. No survivor has been reported from the crash.

The black box of the crashed plane has been found, Egyptian Prime Minister Sherif Ismail said at a press conference.

An investigation commission was established under the order of President Vladimir Putin and Medvedev, and includes Transport Minister Maxim Sokolov and Emergency Situations Minister Vladimir Puchkov, the statement said.

The team also includes rescuers, doctors and representatives from such government departments as the Investigative Committee and Health Ministry.

At least three aircraft are expected to take members of the commission to Egypt, with one already on its way to the crash site, the Tass news agency reported.

Meanwhile, a criminal case was opened into the incident by the Investigative Committee to check on the compliance of laws on flight operating safety.

Investigators would look into documentation and personnel involved in the activities, operations and maintenance of the Airbus A321 to clarify details of the criminal case on the plane crash, the Investigative Committee said in an online statement.

A video footage released by Sinai-based group "Sinai State" purportedly showed that a plane was suddenly caught on fire and fell down, but the video cannot be verified independently for the moment. Endi