Malaysia Airlines Crash: known and not known about the crash.

A summary of what is known and not known about the crash.

Q: Who is responsible?

A: US officials have concluded that the plane was shot down by a Russian-made surface-to-air missile launched from rebel-held territory and that the missile was most likely provided to pro-Moscow separatists by Russia. (US Sees Russian Links in Malaysian Jet's Downing)

Q: How have Russia and separatist groups responded to accusations that they were involved?

A: Both have denied responsibility. Some rebel leaders suggest that Ukraine's armed forces may have shot down the plane. President Vladimir V Putin of Russia said he would assist in an inquiry, but he implicitly blamed Ukraine's government, saying it had created conditions for the uprising. (Rival Claims Over Crashed Malaysia Plane's Recorders)

Q: What kind of missile shot down the plane?

A: US intelligence officials believe the missile responsible for shooting down the plane was a Russian-made SA-11, also known as a Buk or a Gadfly. The SA-11 system fires missiles that are about 18 feet long and have a maximum range of 72,000 feet. Any of the military forces in the area - the pro-Russia separatists, the Ukrainian military and the Russian military - could possess an SA-11. (The Missile That Reportedly Shot Down Malaysian Jet: 10 Facts)

Q: Where was the missile launched from?

A: A US official said the missile was launched near the cities of Torez and Snizhne. (A Family Hit By Both MH17, MH370 Tragedies)

Q: Who is in charge of the crash site?

A: Armed rebel soldiers control the region where the plane's wreckage is. A delegation from the Organization for Security and Cooperation in Europe arrived Friday, but the organization's chairman told Reuters that the crash site had not been sealed off and that the monitors did not have the access they needed. An adviser to the Donetsk provincial governor said that the plane's voice and data recording devices had been recovered by workers from Ukrainian emergency services who were granted access to the crash site but that he did not know who had possession of them.

Q: Why was Flight 17 flying over Ukraine?

A: Flight 17 was flying on an active airway that had been open and in use at higher elevations throughout the conflict in Ukraine. Before the crash, Russia closed part of the airway that the plane would have followed if it had continued into Russian airspace. But the closing applied only to planes traveling under 32,000 feet; the Malaysia flight was above that level. (Malaysia Airlines Crash: Downing of Jet Exposes Defects of Flight Precautions Over Ukraine)

Malaysia Airlines was not alone in flying over eastern Ukraine. A survey of flights to Asia from Europe in the past week found that other airlines were also flying over the region. Some, however, appeared to have been avoiding the area even before the crash.