The European Commission on Friday approved a deal that will see Etihad Airways take a 49-percent stake in Alitalia, effectively rescuing the struggling Italian company.

Brussels gave the merger the go-ahead under the condition that the airlines opened up the Rome-Belgrade route to competitors.

After months of difficult negotiations, Etihad and Alitalia signed a deal on August 8 for the Emirates national carrier to become a shareholder in Italy's flagship but debt-laden airline, in a move that will widen Etihad's reach into the European market.

"The European Commission has cleared... the proposed acquisition," the commission said in a statement.

But it added: "The decision is conditional upon Alitalia CAI and Etihad's commitment to, in particular, release slots to a new entrant at the airports of Rome Fiumicino and Belgrade."

Etihad, based in Abu Dhabi, is expected to invest 560 million euros ($750 million) to become the main stakeholder in the Italian airline, which has lurched from crisis to crisis for years.