Donald Trump and Kamala Harris, the two front-runners for the US presidency, disagree about the broadcaster and date of their first head-to-head debate.

The Harris campaign is attempting to get a debate on ABC News on September 10th, which was supposed to be a debate between Mr. Trump and President Joe Biden.

However, Mr. Trump claims that Mr. Biden's withdrawal from the race "terminated" the ABC debate, and he has instead pushed for a discussion between himself and Ms. Harris on Fox News on September 4.

The pair will face off for the presidency when the US goes to the polls on 5 November.

The disagreement began after President Biden dropped out of the race on 21 July, with Ms Harris immediately becoming favourite to secure the Democratic nomination.

Ever since, Mr. Trump has remained evasive when asked if he would still participate in the debate that was originally slated for ABC News.

To set up new dates, US TV networks have been in negotiations with both campaigns.

On Friday night, Mr. Trump posted on his social media platform Truth Social that he had agreed to Fox News' suggestion for a debate to be held in Pennsylvania, a crucial battleground state, on September 4.

He said that the rules would be the same as his debate with Mr. Biden, and the moderators would be Martha MacCallum and Bret Baier of Fox News.

"If for any reason Kamala is unwilling or unable to debate on that date, I have agreed with Fox to do a major Town Hall on the same September 4th evening," he wrote.

Mr Trump added that the prior agreement has been terminated because Joe Biden is no longer taking part and because his defamation case against the broadcaster would mean there is a conflict of interest.

The Harris campaign has responded saying the former president is "running scared" and is trying to back out of the agreed debate. They said he’s running straight to Fox News – a conservative cable network - to "bail him out".

“He needs to stop playing games and show up to the debate he already committed to on Sept 10," Michael Tyler, Harris Campaign communications director said.

Ms Harris followed up on social media, saying it is interesting how “any time, any place” becomes “one specific time, one specific safe space".

"I’ll be there on September 10th, like he agreed to," she wrote.

Ms Harris’ team said they are open to discussing further debates but only after the agreed one takes place.

If and when the next debate does happen it will be keenly watched to see how the two contenders match up.

Ms Harris secured enough pledges to become the Democratic nominee on Friday.

During a campaign rally in Atlanta on Wednesday, Ms Harris challenged Mr Trump to debate her, saying “if you got something to say, say it to my face".

The debate news comes just hours after a report by the Homeland Security Department revealed that the US Secret Service made mistakes in their response to the 6 January attack on the US Capitol.

Ms Harris, who was then vice-president-elect, came within 20ft (6m) of a "viable" pipe bomb planted outside the Democratic National Committee's headquarters in Washington.

That bomb - and a similar one found at the Republican National Committee headquarters - were placed near the buildings the night before Trump supporters stormed the US Capitol. It remains unclear who planted both pipe bombs.