DUBAI  - Qatar's telecommunications firm Ooredoo's first-quarter profit fell 17 percent, citing challenges in Indonesia, its biggest international market, and Algeria which offset strong contributions from other market such as Myanmar.

Ooredoo made a net profit attributable to shareholders of 486 million riyals ($133.50 million) in the three months ending March 31, 2018, it said in a statement. That compared with 584 million riyals in the same period a year ago.

The result was below SICO Bahrain's forecast of 549 million riyals in net profit, but above EFG Hermes' forecast of 449 million riyals.

"The start of 2018 saw good performances in some of our markets, however challenging market conditions and new regulations impacted the overall performance of the group," said the company's chairman Sheikh Abdulla Bin Mohammed Bin Saud Al-Thani in a statement.

First quarter revenue also dropped 3 percent to 7.76 billion riyals.

Ooredoo said new regulation on SIM card registration in Indonesia hit revenue in its biggest international market.

Indonesia revenue declined 23 percent to 1.5 billion riyals, due to loss of non-compliant customers and a decline in voice and SMS, which is an industry-wide challenge.

Revenue in Algeria was hurt by taxes, weak economic environment and intense competition, it said.

($1 = 3.6405 Qatar riyals)

(Reporting by Saeed Azhar; Editing by Tom Arnold) ((Saeed.Azhar@thomsonreuters.com; +971 44536787; Reuters Messaging: saeed.azhar.reuters.com@reuters.net))