The Star-Spangled banner was afforded an extra star at a Brussels event attended by US Vice President Mike Pence because of “human error”, a European Union official told The Independent.
Calling it a “deeply regrettable” mistake, the spokesman said they would "admit our mistake" and they were "putting in place measures to make sure it will never happen again.”
They added: “We all make mistakes and someone made a mistake and it’s deeply regrettable. I don’t think he noticed. I don’t think anyone noticed until later.”
The famous flag was displayed with 51 stars, instead of 50, when Mr Pence attended a 30-minute news conference with EU leader, Donald Tusk.
The Brussels flag correctly showed 13 stripes, but had three rows of nine stars and three rows with eight stars each.
The US flag typically features nine alternating rows of five or six stars.
The EU flag featuring 12 stars in a circle against a blue background was configured correctly.
Puerto Rico, a US territory, is frequently mistaken as America’s 51st state, and last month, its new representative to Congress pushed a bill that would turn the island into a state by 2025.
Mr Pence, who left the Belgium capital shortly after the conference, appeared to contradict Donald Trump by pledging the US’s “unwavering” commitment to Nato.
Mr Trump has branded the 28-member alliance “obsolete”.
