- NTSB, Boeing to aid Russian investigation
- The Tatarstan Airlines jet had 44 passengers and a crew of six aboard
- The Boeing 737 was flying from Moscow to Kazan when it crashed on landing
- Security official, regional leader's son aboard crashed jet
A Russian jetliner crashed on landing in the city of Kazan, killing all 50 aboard, authorities there reported Sunday.
Tatarstan Airlines flight 363 carried 44 passengers and a crew of six, Emergency Situations Ministry spokeswoman Irina Rossius said. There were no survivors.
The dead included Lt. Gen. Alexander Antonov, the regional chief of Russia's Federal Security Service, and Irek Minnikhanov, the son of Tatarstan regional President Rustam Minnikhanov, Russia's state news service RIA Novosti reported.
A British national was also among those killed, the UK foreign ministry said.
The Boeing 737 took off from Moscow's Domodedovo International Airport, about 700 kilometers (450 miles) west of Kazan, Rossius said.
There was no immediate indication of the cause of the crash, which occurred about 7:25 p.m., the ministry said. Russia's Interstate Aviation Committee has launched an investigation, and the U.S. National Transportation Safety Board and Boeing are assisting.
Boeing said it "extends its deepest condolences to the families of those who perished."
The jet was 23 years old and had been in service with at least eight airlines, including Air France, Uganda Airlines and Bulgaria Air, according to aviation industry websites.
In a November 2012 flight, it was forced to cut short a flight to Moscow and return to Kazan after losing cabin pressure, according to the website AeroInside.
Russia has tried to improve its checkered reputation for air safety in recent years.
In 2011, then-President Dmitry Medvedev grounded two classes of Soviet-era aircraft after a pair of crashes that killed more than 90 people, including a charter plane crash that killed an entire professional hockey team.
Medvedev said Russia would have to upgrade its aircraft fleet, step up safety standards and radically cut the number of airlines.