BRIDGETOWN Barbados (CMC) — Restrictions that temporarily barred United States (US) airlines from operating in parts of the Caribbean and South American airspace were lifted early Sunday, allowing flights to resume after a day of widespread disruptions.

The limits followed multiple Notices to Airmen issued by the Federal Aviation Administration, citing safety risks linked to military activity in Venezuela across the Curacao, Maiquetia, Piarco and San Juan flight information regions.

US Transportation Secretary Sean Duffy said late Saturday that the restrictions expired at midnight eastern time and that airlines were clearing backlogs.

READ: Hundreds of flights cancelled across the Caribbean amid US attack on Venezuela 

He also advised travellers to check directly with carriers as schedules were updated.

United Airlines announced plans to resume Caribbean service, starting with flights to San Juan, Puerto Rico, following hundreds of cancellations at Luis Muñoz Marín International Airport on Saturday.

The airline said it expects to operate most scheduled flights on Sunday and will add extra services to assist affected passengers.

JetBlue has also begun restoring service and may add additional flights. The carrier said about 215 flights were cancelled during the disruption and urged customers to monitor flight status online or through its mobile app.

Meanwhile, in Europe, a conflict-zone advisory for Venezuelan airspace issued by the European Union Aviation Safety Agency remained in effect, but Dutch carrier KLM said it would operate scheduled flights Sunday after cancelling services to several Caribbean destinations a day earlier.