Bernie Sanders has disputed reports that Hillary Clinton has clinched the Democrat presidential nomination – pointing out superdelegates may change their vote ahead of the July Convention.

Clinton was widely reported to have secured the required 2,383 delegates for her to win the nomination of first vote, but Sanders said it was wrong to include Clinton's 571 superdelegate votes as they are unbound – meaning they could change their minds ahead of the 25-28 July vote.

In a statement, Sanders' spokesman Michael Briggs said: "It is unfortunate that the media, in a rush to judgement, are ignoring the Democratic National Committee's clear statement that it is wrong to count the votes of superdelegates before they actually vote at the convention this summer.

"Secretary Clinton does not have and will not have the requisite number of pledged delegates to secure the nomination. She will be dependent on superdelegates who do not vote until July 25 and who can change their minds between now and then.

"They include more than 400 superdelegates who endorsed Secretary Clinton 10 months before the first caucuses and primaries and long before any other candidate was in the race. Our job from now until the convention is to convince those superdelegates that Bernie is by far the strongest candidate against Donald Trump."

Clinton was declared the winner of the Democrat race by AP ahead of the 7 June primaries, in which Sanders has been predicted to do well in California.

She told a rally in Long Beach: "According to the news, we are on the brink of a historic, historic, unprecedented moment, but we still have work to do," The Hill reported, also adding Clinton was planning to reach out to Sanders as the primaries took place.

It is likely Clinton will ask Sanders to suspend his campaign and throw his weight behind her as the frontrunner and likely Democrat candidate. In an interview with Rachel Maddow on MSNBC, Clinton confirmed there was dialogue between the pair.

"Our campaigns are certainly talking. I'll be reaching out after tomorrow night because I obviously want to unite the party. We have so much more in common and we face a serious threat from Donald Trump," said Clinton.

Clinton suspended her own campaign in 2008 in order to back incumbent US president Barack Obama and is clearly hoping for a similar show of support from Sanders, particularly as divisions in the Democrats give strength to GOP presumptive nominee Donald Trump, the only man left in the Republican race.