Ukrainian Prime Minister Arseniy Yatsenyuk said in comments published Sunday that Russia was likely behind the downing of a Malaysian airliner as such an operation takes professionals and not "drunken gorillas".
"Very professional personnel is needed to find targets and fire this missile," he told a German newspaper about the suspected shooting down of Malaysia Airlines flight MH17 over eastern Ukraine which claimed 298 lives.
"It is possible that these kinds of people came from Russia," he was quoted as saying by the newspaper in comments translated into German.
Yatsenyuk suggested it was unlikely pro-Russian separatists alone had fired a missile, as "we known that such such systems can't be operated by drunken gorillas", the Frankfurter Allgemeine Sonntagszeitung reported him as saying.
The premier also said that Ukrainian forces had never used missiles in the conflict and that "all of Ukraine's surface-to-air missiles are stationed elsewhere. We are prepared to make public all evidence and locations."
Yatsenyuk stressed that the conflict in Ukraine was not a civil war but "a Russian-led intervention", describing it as "Russian-led, Russian-backed, Russian-financed and Russian-organised".
He added that "now is the time to stop Russian aggression".
Germany's foreign minister meanwhile demanded that independent investigators quickly be given unhindered access to the site of the downed jet in rebel-controlled eastern Ukraine.
"Anyone who hinders the investigation has something to hide or has no heart," Frank-Walter Steinmeier was quoted as saying in the Bild daily.
He urged an "independent international investigation that is beyond all doubt" and said "the perpetrators and their backers must not get away".