Britain's Prince Harry sat down with former US president Barack Obama for a radio show the prince is guest editing after Christmas, December 18, 2017. ? Reuters

LONDON: Britain's Prince Harry has kept away from opening up a diplomatic rift between the British and US governments over the guest list for his wedding to Meghan Markle and said plans had yet to be finalised.

Asked on a BBC Radio 4?s programme, Today, on Wednesday if he would invite former US President Barack Obama and family to the wedding, Prince Harry ducked the question, saying he didn't want to "ruin that surprise."

"We haven't put the invites or the guest list together yet so who knows whether he's going to be invited or not. I wouldn't want to ruin that surprise," he said.

Speculation is rife in the British media that British officials fear the political consequences if the couple decide to invite Obamas, with whom they are friends, but not President Donald Trump.

Markle, an American actor, has been critical of Trump in the past, and there is already a debate ongoing in the UK over the prospect of an official visit by the US president to the kingdom.

Earlier, British media outlets reported bureaucrats in the British government have been urging Prince Harry not to invite the Obamas to his wedding, due to the fear of upsetting Trump.

A report by The Sun stated that Prince Harry and his fiancée Meghan Markle have informed aides that they want the former US president and his wife to attend the wedding on May 19.

"Harry has made it clear that he wants the Obamas at the wedding," The Sun quoted a senior government source saying. "Trump could react very badly if the Obamas get to a Royal wedding before he has had a chance to meet the Queen."

Prince Harry became good friends with Barack Obama during the Invictus Games.

With relations with the US worsening, there is a fear among British officials that a royal wedding snub would make it impossible for British PM Theresa May to engage with Trump.

The royal wedding is not a state occasion and the government can only offer consultations on the heads of state to be invited.