West Ham's Declan Rice has apologised for historic pro-Irish Republican Army (IRA) posts he made on social media in 2015.

Rice played for Republic of Ireland at youth level and made three senior appearances before switching his allegiance to England – the country of his birth – earlier this year.

The midfielder is in line for his England debut over the next week, but in the last few days comments he made four years ago have resurfaced.

In the posts, Rice wrote "up the RA", a phrase used to support the IRA, a paramilitary organisation which sought to end British rule in Northern Ireland.

Rice has now apologised for his comments, accepting they came from a place of naivety.

On his official Instagram account, Rice wrote: "I am aware that a poorly expressed comment I made when I was a junior player has been circulated on social media.

"I recognise now that my attempt to show support for my team-mates at the time could be negatively interpreted.

"While my naïve words were not meant to be a political opinion and do not represent who I am, I sincerely apologise for any offence caused."

England manager Gareth Southgate does not think Rice should be judged too harshly for things he said several years ago about a subject he did not know a great deal about, and he expects supporters will understand it said more about his immaturity than any political standing.

"He's apologised," Southgate told reporters on Thursday. "It's not representative of what he believes and what he feels.

"Outside of that, it was when he was 15 or 16 and engaged in conversation with friends. We've all probably said things, written things that would look different several years later.

"I think people understand. Most people will have children of those kind of ages. They are still maturing.

"You can get giddy or say things you don't know much about. Our fans or our public will understand that fact."