(Reuters) - United Airlines said on Thursday the U.S. Federal Aviation Administration has permitted the carrier to restart its certification activities, including new aircraft and routes.

The airline's certification activities were suspended after the FAA said in March it was increasing its oversight of United following recent safety incidents. The aviation regulator said it would initiate a formal evaluation to ensure the Chicago-based carrier was complying with safety regulations.

"We will continue to see an FAA presence in our operation as they review our work processes, manuals and facilities," United Airlines said in a statement.

The airline delayed the start of two new international routes last month, citing a pause on some certifications by the FAA.