KUALA LUMPUR (REUTERS) - Malaysia Airlines System Bhd (MAS) shares fell sharply on Friday on news one of its planes was downed in Ukraine, raising pressure on the state-run carrier to try to restore investor confidence after the second major disaster in months.

A passenger plane bound for Kuala Lumpur from Amsterdam was downed over eastern Ukraine on Thursday, killing all 298 people on board. Shares of MAS, the most heavily traded stock on Friday morning, fell to a one-month low of 18.8 sen.

"Sentiment was already negative, and this just makes it worse," an analyst with AmResearch told Reuters, referring to the mystery of Flight MH370 which went missing in March on a flight from Kuala Lumpur to Beijing with 239 passengers, many of them Chinese, and crew on board.

"There was a lot of anti-Malaysia sentiment in China after MH370. We have to see if this situation will have the same effect and lead to a heavy sell-down," he said.

Hit by slumping ticket sales after the disappearance of MH370, MAS turned in its worst quarterly performance in two years in the January-March period and is currently exhausting its operating cash.

"MAS is the victim in the case," said Tan Kam Meng, an analyst with TA Research. "It was not human error or negligence. I don't think this will affect travel sentiment."

Malaysian state investor Khazanah Nasional Bhd plans to take MAS private as the first step in a major restructuring of the airline, two people with direct knowledge of the matter told Reuters earlier this month.