Hillary Clinton, Bernie Sanders debate in Miami

Democratic presidential candidates, Hillary Clinton and Sen. Bernie Sanders, I-Vt, stand together before the start of the Univision, Washington Post Democratic presidential debate at Miami-Dade College, Wednesday, March 9, 2016, in Miami, Fla. (AP Photo/Wilfredo Lee)

Although Bernie Sanders this week reaffirmed his commitment to defeating presumptive Republican presidential nominee Donald Trump, the Democratic White House hopeful said he has yet to reach the point where he's ready to endorse rival Hillary Clinton.

The Vermont senator, who has shifted his focus toward impacting the Democratic Party's platform in recent weeks, told MSNBC late Thursday that he is working with Clinton's campaign to push the former secretary of state to embrace policies he championed in the primary.

"Whether it is on moving toward making public colleges and universities tuition-free, or moving very aggressively in terms of health care and moving us toward a universal health care system, significantly expanding primary health care, those are the issues that we're working with Secretary Clinton on now and I hope we can be successful," he said.

Sanders added that he will do everything he can to block Trump from the White House, calling the businessman "a pathological liar" and accusing him of wanting "to give hundreds of billions of dollars in tax breaks to the top two-tenths of one percent by repealing the estate tax."

More importantly, the senator argued, the U.S. "cannot have a president who goes around insulting Mexicans, Latinos, Muslims, women and African-Americans."

"That's just outrageous. So I'm going to do everything that I can to see that Donald Trump is defeated," he said.

Asked if he would hit the campaign trail for Clinton, Sanders said his focus will largely be on shaping the Democratic Party's platform.

"We are working, as we speak, we are working with the Clinton campaign, trying to be able to come forward and say to my supporters out there, you know what, here's the progress that we have made ... so I hope that we can reach that goal," he said. "We are not there at this moment."

Sanders further hit back against Trump's claim that he "hates" Clinton.

"Of course Trump is lying, as he always does," he said. "No, I do not hate Secretary Clinton. I've known her for 25 yeas, I have a lot of respect for her, we've worked together. We have disagreements on issues, but to say that I hate her is absolutely untrue."

The Vermont senator, who has pledged to take his campaign to the Democratic National Convention in Philadelphia later this month, recently offered that he would vote for the former first lady in November if she becomes the party's nominee.

He, however, has yet to endorse his Democratic rival -- a move Vice President Joe Biden told NPR Thursday was imminent.

"Oh, I've talked to Bernie, Bernie's going to endorse her, this is going to work out," he said. "The Democrats are coalescing even before this occurs."