Philadelphia, Jul 26 (IANS): Vermont Senator Bernie Sanders was booed by his own delegates after calling on them to support presumptive presidential nominee Hillary Clinton on the opening day of a Democratic National Convention (DNC) here on Monday evening.

Sanders lamented his 2016 primary loss but insisted that "Hillary Clinton must become the next president of the US", NBC News reported.

"This election is about which candidate understands the real problems facing this country and has offered real solutions - not just bombast, fear-mongering, name-calling and divisiveness," Politico quoted Sanders as saying.

"We need leadership in this country which will improve the lives of working families, the children, the elderly, the sick and the poor. We need leadership which brings our people together and makes us stronger - not leadership which insults Latinos, Muslims, women, African-Americans and veterans - and divides us up."

"By these measures," he continued, "any objective observer will conclude that - based on her ideas and her leadership - Hillary Clinton must become the next president of the United States. The choice is not even close," Politico reported.

The former presidential hopeful received a rousing round of applause, and also some "Bernie!", "We want Bernie!" and "Take it to the floor!" chants from his nearly 1,900 characteristically enthusiastic supporters.

Sanders supporters' cheers and applause drowned out the Vermont Senator for several minutes when he first took the stage at the DNC for a prime time address. Several supporters appeared to have tears in their eyes during Sanders' appearance.

Sanders addressed his "disappointed" supporters, who have been a vocal presence throughout the first day of the Convention, NBC News said.

They booed and jeered outgoing DNC Chairwoman Debbie Wasserman Schultz earlier on Monday.

During a speech, they even booed Sanders when he mentioned Clinton by name.

The Vermont senator also hit on the major themes of his campaign, including income inequality and Wall Street malfeasance, money in politics and universal health care.

"Hillary Clinton will make an outstanding president, and I am proud to stand with her tonight," NBC News quoted Sanders as saying.

According to a recent NBC/Wall Street Journal poll, 76 per cent of Sanders supporters said they would vote for Clinton against Republican rival Donald Trump.

According to CNN, Sanders spent much of Monday making a last-ditch effort to quell the anger among his backers, including texting supporters asking them not to "engage in any kind of protest" on the floor.

"Our job now is to see that platform implemented by a Democratic Senate, a Democratic House and a Hillary Clinton presidency - and I am going to do everything I can to make that happen," Sanders said while concluding his speech.

The DNC which opened on Monday night will last until Thursday evening.

Delegates from 50 states on Tuesday will officially select Clinton as the first female presidential nominee of one of the country's two biggest parties.

Clinton will formally accept the nomination on Thursday evening with a speech closing out the convention after being introduced to the assembled delegates by her daughter Chelsea.