President Barack Obama has formally endorsed Hillary Clinton for president.

"I want you to be the first to know that I'm with her," he says in a video posted online Thursday by the Clinton campaign. Obama called on Democrats to unify behind the former secretary of state.

Clinton and Obama will campaign together in Green Bay, Wisconsin, on June 15.

Obama met with Clinton's rival, Bernie Sanders, at the White House earlier Thursday, where they had a "wide-ranging discussion" about a range of issues, including income inequality and problems that working families face.

A spokesman for Sanders said that Sanders requested the meeting.

Afterward Sanders reiterated the issues that he has campaigned to change -- college debt, crumbling infrastructure, inadequate social security and health care and the wealthy's influence on politics.

Sanders promised to continue his campaign run at least through next week's primary in the District of Columbia.

Meanwhile, Senate Minority Leader Harry Reid said Sanders is invited to join a Democratic caucus meeting next week.

Information from The Associated Press was used in this report.

Democratic primary delegate count in 3 graphics

The delegate count

Delegates by state

Delegates allocated over time