ABU DHABI, July 26 (Reuters) - First Abu Dhabi Bank , created by a merger of National Bank of Abu Dhabi and First Gulf Bank on Wednesday reported a net profit of 2.56 billion dirhams ($697.5 million) for the second quarter.

Based on a "pro-forma" basis, the net profit was down from 2.68 billion dirhams from a year earlier, primarily due to slower business momentum.

This is the first combined results of Abu Dhabi's two biggest banks, First Gulf Bank and National Bank of Abu Dhabi, after their merger in April to create one of the largest banks in the Middle East and Africa.

EFG Hermes had projected a profit of 2.57 billion dirhams for the combined bank.

First Abu Dhabi Bank, which reported assets of 625 billion dirhams, said the integration progress was firmly on track but didn't say when it will be completed.

It said operating expenses dropped 6 percent during the quarter from the year earlier period to 1.38 billion dirhams, while impairment charges fell 12 percent to 611 million dirhams.

(Reporting By Stanley Carvalho, editing by Saeed Azhar) ((stanley.carvalho@thomsonreuters.com; + 9712 6444431; Reuters Messaging: stanley.carvalho.thomsonreuters.com@reuters.net))