BOSTON — The Nuclear Regulatory Commission approved the renewal of the Pilgrim Nuclear Power Station’s operating license for another 20 years, the agency announced, despite objections from Gov. Deval Patrick and other Massachusetts officials.

The commission voted 3-1 to authorize staff to renew the license before June 8, when the original 40-year license of the Plymouth, Mass., facility was set to expire.

Patrick called the NRC’s decision issued Friday “extremely troubling.” He and other officials, including Attorney General Martha Coakley and U.S. Reps. Edward Markey and William Keating, had called on the NRC to hold off on renewal until all safety and environmental contentions had been resolved.

The commission approved an earlier staff recommendation to relicense the plant, even though some issues regarding its operation were still under review.

Outgoing commission chairman Gregory Jaczko cast the dissenting vote, while Commissioners Kristine Svinicki, William Magwood and William Ostendorff approved the relicensing, according to NRC records. The fifth member of the commission, George Apostolakis, abstained from the vote because he had previously reviewed Pilgrim’s application while serving on an advisory panel, an NRC spokesman said.

John Herron, president and chief executive of the plant’s owner, Entergy Nuclear, said the NRC’s decision came after it conducted “extremely thorough safety and environmental reviews” of the plant.

“The decision ensures Pilgrim’s generation of safe, clean, reliable and low-cost energy will continue to benefit the New England area, as will the plant’s existing 650 jobs and its $135 million in annual economic impact,” Herron said.

Neil Sheehan, an NRC spokesman, noted that Pilgrim’s application had been submitted on Jan. 27, 2006, and that the 6 1/2 year review period was the longest of any other renewal application in the agency’s history. He said NRC staff devoted approximately 14,600 hours to reviewing the application.

“The NRC’s decision to approve the renewal of Pilgrim’s operating license without addressing public and environmental safety issues is extremely troubling,” Patrick said in a statement Friday.

“Renewing the license before those concerns are alleviated is irresponsible and misguided,” he added.

Coakley had cited what she said were unaddressed safety concerns raised by the accident at the Fukushima Dai-ichi nuclear plant following the earthquake and tsunami in Japan last year. She noted Pilgrim’s method of storing spent fuel rods was the same method used by Fukishma.

Christopher Loh, a spokesman for the attorney general, indicated that the office would pursue appeals through the courts and “other appropriate channels.”

The NRC said if the license renewal were to be put aside on appeal, Pilgrim’s previous license would be reinstated and the plant could continue to operate pending the final outcome of any appeal.

Mary Lambert, an anti-Pilgrim activist from Duxbury, said granting the license before the hearing process was completed was like ending a football game in the middle of the fourth quarter.

“When the regulator does not follow its own rules, don’t expect that it will require the nuclear industry to do so either. Fukushima showed what happens,” said Lambert, who heads the group PilgrimWatch.

Critics had also raised concerns about plant security and emergency planning, and how relicensing would affect Atlantic sturgeon and river herring, which swim nearby the plant and are protected under the federal Endangered Species Act.

Jaczko, who this month announced his resignation, urged fellow commissioners in his written comments to delay their votes while litigation against Pilgrim remains unresolved.

Robert Smith, Pilgrim’s site vice president, said Entergy was able to demonstrate to the NRC that the plant could operate safely for the next 20 years.

The company said the 688-megawatt plant, built in 1972, generates enough power to meet nearly 10 percent of the state’s electrical needs.