* Aviation authority recommends airlines avoid all crisis areas
* Lufthansa seeks more specific information
* Pilots' union says assumptions have changed after MH17 (Adds Lufthansa comment)
BERLIN, July 18 (Reuters) - German authorities have warned airlines against flying over all crisis zones, not just eastern Ukraine, a spokesman for the transport ministry said on Friday.
After Malaysia Airlines flight MH17 was downed on Thursday over an area where rebels are fighting Ukrainian forces, killing all 298 people on board, questions have been raised as to why airlines were flying over a conflict zone.
Airlines on Thursday diverted their planes and Ukraine on Friday closed its airspace over the area.
Germany has now gone one step further by including all conflict zones in a warning sent out by the Federal Aviation Authority (LBA) to Germany's 144 aviation firms.
That would appear to include other regions such as Syria, Iraq and Afghanistan. But it is up to individual countries to close their own airspace, as Ukraine did on Friday.
Lufthansa, Germany's main airline, said it was in touch with the LBA to get more precise information on what crisis zones it was referring to.
"We expect the LBA to give more specific information on its recommendation as soon as possible, in case there have been definite changes to the security situation in certain areas," a spokesman said.
Joerg Handwerg, a board member at German pilots' union Vereinigung Cockpit and an A320 captain, earlier told Reuters that questions must be asked over whether planes should be allowed to fly over conflict zones.
"Flying over contested territories such as Afghanistan was previously thought of as unproblematic, because there were no weapons that could reach passenger planes at the altitudes they fly," Handwerg, who flies medium-haul planes, told Reuters.
"From the point of view of pilots, the threat was of a different quality before. There were only a few flights that were classed as critical ... But now planes flying at 10,000 metres above the entire country are a risk." (Reporting by Markus Wackert and Peter Maushagen; Writing by Victoria Bryan; Editing by Mike Collett-White)