BEIJING - China's quality watchdog said Sunday that over 4,000 escalators and elevators have been suspended over safety concerns during a nationwide safety-check campaign.

By the end of July, more than 10,000 escalators and elevators had been identified by local quality authorities as having potential safety problems, according to the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ).

"After repairs and maintenance, more than 4,000 escalators or elevators remain suspended for use," said the AQSIQ.

The safety checks came after an ascending escalator on Beijing subway Line 4, an Otis 513 MPE, suddenly reversed, and killed a 13-year-old boy and injured 30 others earlier this month.