(Adds FDA comment, paragraph 3)

LONDON, March 11 (Reuters) - European and U.S. regulators are reviewing the safety of Gilead Sciences' leukaemia drug Zydelig due to concerns over serious adverse events, including deaths.

The actions were prompted by an increased rate of harmful events, mostly due to infections, seen in three clinical trials that tested the drug in combination with other cancer medicines, the European Medicines Agency (EMA) said on Friday.

Separately, the U.S. Food and Drug Administration said it is "aware of and is looking into reports of deaths" in clinical trials involving Zydelig, according to an emailed statement from agency spokeswoman Angela Stark.

The FDA said it will communicate new safety-related information on Zydelig as it becomes available.

The EMA said it would review data from the studies to see if the findings had any consequences for Zydelig's approved use. In the meantime, patients taking the drug should be carefully monitored for signs of infections, it said.

The European agency added it was considering whether any other immediate measures were necessary while the review was ongoing.

Zydelig is authorised in Europe for treating chronic lymphocytic leukaemia (CLL) in combination with Roche's Rituxan and on its own for treating follicular lymphoma. It is also approved in the U.S. for treatment of small lymphocytic lymphoma.

(Reporting by Ben Hirschler, editing by Ed Osmond and Bernard Orr)