* Pan-European FTSEurofirst index down 0.7 pct
* Investors spooked by prospect of September rate rise
* Amadeus falls as Air France mulls ticket levy
By Atul Prakash and Liisa Tuhkanen
LONDON, June 9 (Reuters) - European shares slipped to a 3-1/2-month low on Tuesday in a global sell-off in equities on mounting concern over the impact of a U.S. rate hike cycle from as early as September prompting European investors to cut risks.
The FTSEurofirst 300 index of top European shares fell for a sixth straight session and was down 0.7 percent at 1,518.23 points by 1217 GMT after falling to a low of 1,507.72, the lowest since mid-February. The index has fallen more than 7 percent in the past two weeks.
The sell-off followed a fall in U.S. shares on Monday and in Asia overnight, following a series of encouraging U.S. reports in the recent past, including stronger-than-expected May jobs data, prompting expectations of a Fed rate hike in September, sooner than some expected.
"We have had a pickup in some of the U.S. economic indicators and this development tends to go hand in hand with increasing rate hikes fears," Robert Parkes, equity strategist at HSBC Global Research, said.
"We are not dismissing the potential for short-term volatility, but fundamentally we see the market remaining supported in the longer term. We expect earnings growth to come in significantly ahead of expectations this year and that, combined with the ongoing quantitative easing in Europe, will keep the bull market intact."
Spain's Amadeus led the decliners in Europe. Shares in the Spanish travel IT firm fell 3.6 percent to 35.24 euros as Air France-KLM said it was considering following a move by Lufthansa to levy a charge on tickets booked via third parties on global distribution systems.
Amadeus would have to use a different system to avoid the charge. Its stock is down nearly 15 percent in June, with broker Kepler Chevreux cutting its target price on Amadeus to 39.20 euros from 43 euros, saying Lufthansa's move added uncertainties to Amadeus' outlook.
"This new strategy raises concerns about the whole business model of GDS companies," analysts at the brokerage said in a note. "Lufthansa's move could be used as a marketing tool by other companies, which will be keeping a close eye on how things pan out."
Investors also kept an eye on negotiations between Greece and its international creditors. The European Commission has received a new proposal from Greece on Tuesday, the day after German Chancellor Angela Merkel warned that time was running out for a reform-for-aid deal to keep the country in the euro.
Among other movers, Deutsche Bank fell 2.5 percent after Germany's largest lender said its offices in Frankfurt were searched by German prosecutors seeking evidence related to client securities transactions.
HSBC dropped 1.2 percent after investors and analysts questioned whether the pledge to shed almost 50,000 jobs would be enough to lift earnings.
On the positive side, Reed Elsevier rose 2.4 percent after Barclays upgraded the stock to "overweight" from "equal-weight".
Europe bourses in 2015: link.reuters.com/pap87v
Asset performance in 2015: link.reuters.com/gap87v
Today's European research round-up (Additional reporting by Alistair Smout)