Mobile phone maker Motorola Mobility is to cut 4,000 staff worldwide as part of efforts to return to profitability.

This job losses are the equivalent of 20% of its workforce.

The firm, bought by Google last year, said it planned to close or merge about one third of its 90 facilities which include offices and factories.

US-based Motorola also announced a shift in emphasis away from low-cost non-smartphones to "more innovative and profitable devices".

Two-thirds of the jobs will go outside of the US, Google said. It expects the cost of severance packages to be $275m.

"Motorola is committed to helping them through this difficult transition and will be providing generous severance packages, as well as outplacement services to help people find new jobs," a statement said.

The firm would not comment on exactly where the jobs would be cut. It employs 250 staff in the UK at three sites; Basingstoke, Livingstone and Swindon, BBC News reported.