Boeing and US aviation regulators say the company needs more time to finish changes in a flight-control system suspected of playing a role in two deadly crashes. The Federal Aviation Administration said on Monday that it anticipates Boeing's final software improvements for 737 Max airliners "in the coming weeks." Boeing was expected to complete the work last week, but FAA spokesman Greg Martin said the company needs more time to make sure it has identified and addressed all issues.

Chicago-based Boeing offered the same timetable as it works to convince regulators that it can fix software on the planes. "Safety is our first priority, and we will take a thorough and methodical approach to the development and testing of the update to ensure we take the time to get it right," said Boeing spokesman Charles Bickers.