FBI Investigators in the United States have opened an investigation after sewing needles were found in sandwiches served on board Delta Air Lines flights. 

Four Delta flights, all from the Netherlands to the US, were involved in the incident, with the sandwiches having been prepared by Amsterdam-based Gate Gourmet.

One person, flying to Minneapolis, was injured.

In a statement Delta said it was cooperating with the FBI and taking the matter “extremely seriously”.

Needles were also found on two flights to Atlanta and one to Seattle.

Delta spokeswoman Kristin Baur told the Associated Press flight attendants stopped serving the sandwiches as soon as the first needle was discovered.

Attendants were also able to alert other flights.

Passengers were served pizza instead.