Russian emergency workers searched heaps of twisted metal and tall grass for clues about what caused two airliners to crash within minutes of each other, killing all 89 people aboard.

Officials said one jet sent a hijack distress signal, raising fears terrorists had struck.

Flight recorders from both planes were found and taken to Moscow for investigation.

Russian security authorities said that explosives specialists were still working at the scene of the crashes.

They reported that terrorism remained a possible cause, although there was no evidence so far that terrorists were behind the tragedies.

Federal Security Service spokesman Sergei Ignatchenko said investigators were still questioning airport officials and airline and security employees at Domodedovo Airport, from which both flights left 45 minutes apart.

The FSB said they were investigating other possibilities such as technical failures, the use of poor quality fuel, breaches of fueling regulations and pilot error. Rain and thunder was reported in the regions where both crashes occurred.

Source: CRIENGLISH.com