SOCHI, Russia — Russia mounted an expansive search-and-recovery operation in the Black Sea on Monday for the passengers and the fuselage of a military passenger plane that crashed a day earlier, killing all 92 people on board, including dozens of members of a storied army choir.

In Moscow, famous performers and ordinary citizens, some of them in tears, dropped flowers at the entrance to the headquarters of the choir, the Alexandrov Ensemble. Another mountain of red carnations and candles piled up outside the Ostankino television center, as a tribute to nine journalists who were accompanying the choir to the Khmeimim Air Base in Syria.

The plane was carrying 68 performers and staff members of the ensemble, including an army choir and orchestra loved for its renditions of classical Russian songs and folk tunes.

The most likely area where the plane plunged into the water moments after taking off from the southwestern resort city of Sochi has been identified, Lt. Gen. Viktor N. Bondarev, commander of the Russian Air Force, said at an early morning news conference at the airport.

General Bondarev said that he did not expect the plane’s fin, where the flight recorders are situated, to be as damaged as the fuselage, raising hopes that the recorders might be intact. Several chunks of the fuselage were located on Monday on the seabed about a mile offshore, initially by sonar and then by divers, the Ministry of Emergency Situations announced.

The transportation minister, Maxim Sokolov, who is leading a commission looking into the crash, said that terrorism had not been ruled out, but that it was unlikely to be the cause of the crash of the Tupolev 154, which was flying members of the choir and others to Syria for a New Year’s Eve concert for troops stationed at an air base near Latakia.

“In order to organize our work, we need to understand what happened,” Mr. Sokolov said at the news conference. “As far as we know, the main versions do not include the terrorist act, so we base our work on the premise that technical malfunction or pilot’s error caused the catastrophe.”

Some analysts have pointed to the possibility of terrorism, citing the sudden disappearance of the airplane from radar screens and the lack of an emergency call from the pilot.

At the same time, officials emphasized that the airplane should have been technically sound, because it underwent repairs and resumed service in December 2014, and the pilot was experienced and had 1,900 hours of flying time at the control of Tupolev 154s.

“The plane was technically fit,” General Bondarev told the news conference. “The pilot was well prepared.”

Criminal investigators as well as a Defense Ministry committee are in charge of determining the cause of the crash.

Search efforts involving 45 ships and 135 divers continued on Monday. The bodies of 10 victims, as well as dozens of body parts that have been recovered, were flown to Moscow for identification, Russian officials said at the news conference.

The government discouraged relatives of those on board from coming to Sochi during what was expected to be a long recovery operation, and the few that had done so were being isolated from journalists.

The plane took off from Chkalovsky military airfield near Moscow and stopped in Sochi for refueling before crashing at 5:27 a.m. about a mile from the shore.

Russia observed a national day of mourning on Monday, with the main government television channels repeatedly playing mournful music and eulogizing those killed. A memorial service was conducted at a small chapel inside the Sochi terminal, with the airport’s employees and passers-by carrying flowers and candles.

In Khosta, a suburb of Sochi, security guards cordoned off a long strip of seashore. A number of men perused the pebbled beach looking for traces of material from the doomed jetliner.

At a makeshift memorial heaped with flowers near Sochi’s old seaport, Oganes G. Melikyan recalled his old army friend, Valery M. Khalilov, who was the artistic director of the ensemble.

“He was extraordinarily intelligent with a great sense of humor,” Mr. Melikyan, a 58-year-old construction worker, said as he held photographs of the orchestra from his own days in the army.

“Kind and good are not enough to describe him,” said the army veteran, adding that news of the death hit him “like a ton of bricks fell on my head.”

Several couples were ensnared in the disaster, according to various Russian news reports. Dmitri Papkin, 35, a choir singer, was on an earlier plane that had already arrived in Syria. His wife, Maria Klokotkova, 34, believed to be in the dance troupe, died on the second flight.

Mikhail Vasin, 25, a basso profundo in the choir, proposed to Ralina Gilmanova, a 22-year-old ballerina, last New Year’s Eve. She accepted, and the couple were planning to get married early in 2017. Both were aboard the flight that crashed.

Scattered band members survived because they did not go on the trip. The lead soloist, Vadim P. Ananyev, had stayed home to help his wife with their newborn. The stunned singer told the daily Komsomolskaya Pravda, “I don’t even have the words” to describe the tragedy.

The civilians on board included Yelizaveta P. Glinka, a prominent philanthropist who received a state award this month from President Vladimir V. Putin for her humanitarian work. She was taking a shipment of medicine to Syria.

“We never know if we will return alive, because war is hell on earth, and I know what I am talking about,” Ms. Glinka said at the award-presentation ceremony in the Kremlin. “But we are sure that goodness, compassion and mercy are more powerful than any weapon.”

The Tupolev 154 was once a workhorse of the Soviet air transportation system. Most civilian airlines have phased them out, but they are still used by government agencies. The plane that crashed over the weekend was built in 1983.

Russia deployed military forces to Syria in September 2015, mainly air force bombers. Mr. Putin said at the time that he was sending forces there to fight Islamic extremists, but so far the main goal appears to have been shoring up the rule of President Bashar al-Assad. Syrian government forces with Russian backing recaptured the eastern half of Aleppo, a key rebel stronghold, last week.

The Russian plane crash was the second deadly episode in a week linked to Syria, after Moscow’s ambassador to Turkey was assassinated on Dec. 19 by a Turkish gunman saying he was taking revenge for Aleppo.

After another crash last year, when a Russian civilian Airbus went down in the Sinai Peninsula, killing all 224 people on board, the Russian authorities did not confirm for weeks that a bomb had been responsible, despite the Islamic State claiming responsibility hours after the episode.

Source: NYTimes