Mexican state oil giant Pemex expects to meet its 2015 output target of 646,000 barrels per day (bpd) for the oil-producing region where a platform exploded last week, killing four people and leaving three more missing, a top executive said on Sunday.

The fire broke out on Pemex's Abkatun Permanente processing platform in the oil-rich Bay of Campeche at 3.40 a.m. local time on Wednesday, leading to the evacuation of 302 people. The blaze was not extinguished until 7.30 p.m that evening.

Speaking in a televised conference from Ciudad del Carmen, on the Gulf of Mexico, Gustavo Hernandez, Pemex's head of exploration and production, said the incident had led Pemex to shutter production of about 220,000 bpd, with some 170,000 bpd coming back online between Sunday and Monday.

"The original 2015 production target for the Southeast Marine Region of 646,000 bpd of oil will be met," Pemex said in a document accompanying Hernandez' press conference.

Mexico is the world's No. 10 crude producer at just under 2.3 million bpd, down about a third from a peak of 3.4 million bpd in 2004. Part of the Abkatun Pol Chuc offshore complex, the damaged platform separates crude oil and gas from various wells.

Hernandez said it was not yet known what started the fire, adding that investigators were in the process of gaining access to the site to ascertain the cause.

Hernandez also said that efforts were still underway to find three people still missing.

"The search is ongoing, and so is the support of the Mexican navy," he said. "We won't stop until we've found them."

Pemex has had a number of accidents in recent years and the latest one comes as Mexico seeks to lure private investors to revive its flagging oil industry.

In 2013, at least 37 people were killed by a blast at Pemex's Mexico City headquarters, and another 26 people died in a fire at a Pemex natural gas facility in northern Mexico in September 2012.

Last year, Mexico finalized a reform to end Pemex's 75-year-old oil and gas monopoly, but expectations of a boom in private investment have been tempered by the plunge in global crude prices.