WASHINGTON, June 6 (Xinhua) -- U.S. Democratic presidential candidate Hillary Clinton on Monday reached the number of 2,383 delegates needed to become the first-ever female nominee of a major political party in the United States, according to the latest AP delegate count.

The former first lady and secretary of state garnered 1,812 pledged delegates won in primaries and caucuses, plus the support of 571 superdelegates -- party leaders who can choose whom to support at the national convention, the AP reported.

Though Clinton's nomination would not become official until the party holds convention in Philadelphia in July, Robby Mook, her top campaign aide, already hailed the news as "an important milestone."

Shortly after the news, the Bernie Sanders campaign said it is too early for the media to call the race, reiterating that superdelegates can still change their minds between now and the July national convention.

"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," said Michael Briggs, the spokesman for Sanders.

"Our job from now until the convention is to convince those superdelegates that Bernie is by far the strongest candidate against Donald Trump," he said in a statement.

Sanders, with 1,521 delegates and 48 superdelegates currently, is widely thought unlikely to sway superdelegates to his side, as Clinton has won more votes, more states, more pledged delegates and more superdelegates.

The news came one day before the last Super Tuesday during the whole primary process starting on Feb. 1. Six states, including California, New Jersey, New Mexico, South Dakota and Montana, are all set to vote Tuesday.

Many U.S. media have already prepared to call the race on Tuesday, especially when the poll closes in 142-delegate New Jersey where Clinton holds a solid lead, 61 percent to 34 percent over Sanders.

Sanders defiantly vowed again earlier on Sunday to take his campaign to the Democratic National Convention in July even if Clinton garners enough delegates to reach the threshold for securing the nomination.