The Mayor of Boston and the Governor of Massachusetts have both said they won’t march in the city’s St Patricks’ day parade after a gay veterans group was banned.

OutVets on Facebook said they were excluded from the South Boston parade on 19 March.

Writing on the social media site, the group said: “While the reason for our denial is unclear, one can only assume it’s because we are LGBTQ”.

The ban came as a surprise as OutVets has been allowed to march in the parade for the past two years.

According to CBS, the South Boston Allied War Veterans Council, which organises the St Patrick’s Day event, voted 9-4 to exclude the group.

Marty Walsh, the Mayor of Boston said in a statement: “I will not tolerate discrimination in our city of any form. We are one Boston, which means we are a fully inclusive city. I will not be marching in the parade unless this is resolved. Anyone who values what our city stands for should do the same.”

Governor Charlie Baker added that he would not march if the group is excluded.

He said: “Veterans’ groups should be allowed to march in the parade. If veterans’ groups aren’t allowed to march in that parade, I will probably do something else. I won’t march.

The decision to ban the group has been widely condemned, including by Congressman Seth Moulton who said the decision was “outrageous”.

Moulton said: “Let’s just be clear, these are men and women who courageously put their lives on the line for our country.”

OutVets had previously been excluded by the Allied War Veterans Council, but was allowed to march in 2015, after Mayor Walsh threatened to boycott the event.

After the decision was reversed in 2014, the LGBT+ veterans group was allowed to march in 2015 and 2016.

It is unclear why they have been again excluded this year.

The city of Boston last year joined the likes of San Francisco and New York City in stopping its workers from travelling to the state of North Carolina over the state’s anti-LGBT ‘bathroom’ law.