* Telecom Italia up on report Vivendi to increase stake
* Rise in oil price lifts energy stocks
* Greece concerns, U.S. rate hike prospect dampens sentiment
* Europe bourses in 2015: link.reuters.com/pap87v
* Asset performance in 2015: link.reuters.com/gap87v
By Sudip Kar-Gupta
LONDON, June 17 (Reuters) - European stock markets edged lower on Wednesday, as lingering concerns over Greece's debt problems offset gains in Telecom Italia and energy shares.
Traders were also reluctant to add to equity positions before a U.S. Federal Reserve meeting later in the day, with many investors expecting the Fed to signal that U.S. interest rates will be increased in September.
Athens' benchmark ATG equity index edged down 0.3 percent, with the broader, pan-European FTSEurofirst 300 index slipping 0.1 percent. Germany's DAX fell 0.1 percent, while France's CAC declined 0.5 percent.
However, Telecom Italia outperformed to rise 3.7 percent after sources told Reuters that Vivendi was planning to increase its stake in the Italian group.
A rise in Brent crude oil prices also boosted energy stocks .
Nevertheless, some traders said they would look to use any bounce in share prices as a cue to sell, given the concerns in the background over the Greek debt deadlock, with Athens facing payments to creditors by the end of June.
"We're looking to sell into strength here," said Darren Easton, director at Logic Investments.
Greek Prime Minister Alexis Tsipras has accused Greece's creditors of trying to "humiliate" Greeks with more cuts, while there has been a growing drum beat of warnings that Europe is preparing for Greece to leave the euro zone.
Easton said the DAX could fall by 1,000-2,000 points if Greece did end up leaving the euro zone.
"We're not ruling out an agreement on Greece being formed, but I wouldn't be surprised if they drag it out and the market has another setback before the end of the month," he added.
The Athens' ATG equity index has fallen around 15 percent since the start of 2015, underperforming a 12 percent advance on the FTSEurofirst 300.
Economic stimulus measures from the European Central Bank (ECB) have cushioned the blows from Greece on other European economies.
Some investors said any Greek debt default may only have a limited impact on the broader market, pointing to how Greece only represents a small amount of the European economy and highlighting the ongoing monetary support from the ECB.
"Even if it comes to a default, the broader market impact should be limited," said Trevor Greetham, head of multi asset at Royal London Asset Management.
Today's European research round-up (Editing by David Goodman and Louise Heavens)