In the three months to June 30, production rose 9 percent compared to the previous quarter to 313,302 ounces of gold while profit from mining increased by 6 percent, the London-listed miner said in a statement.

Randgold maintained its annual targets of gold production reaching between 1.3-1.35 million ounces at a cost of between $590-$640 per ounce.

A strike at Randgold's Tongon mine in Ivory Coast, which started on July 13, has crippled production and followed similar stoppages at the operation earlier this year.

"The Tongon work stoppage is obviously a challenge, but we take comfort from the government's leadership in ensuring measures are taken to protect the assets and that they are dealing with the situation," Chief Executive Mark Bristow said.

He said Randgold was still assessing the strike's impact but that annual targets for the group were maintained due to a strong performance at the Kibali mine.

Tongon, which accounted for 22 percent of Randgold's 2017 total production, recorded a 12 percent increase in output in the second quarter but its 2018 target was lowered to 250,000 ounces from 290,000 ounces previously.

(Reporting by Zandi Shabalala; editing by Jason Neely)