Sen. Elizabeth Warren, D-Mass., a member of the Senate Banking and Urban Affairs Committee, listens to testimony by Federal Reserve Board Chair Janet Yellen as she delivers her semi-annual report on monetary policy, July 16, 2015. Reuters

Wall Street foe Elizabeth Warren approves of Donald Trump's tax plan. Warren, the Democratic Massachusetts senator known for railing against policies that benefit the rich and the financial sector, said Tuesday she could get behind Trump's proposal to raise taxes on the wealthiest.

"There are a lot of places where he gets out and talks about important things," Warren said during an appearance on ABC's "The View." "Donald Trump and I both agree that there ought to be more taxation of the billionaires, the people who are making their money on Wall Street."

Warren's praise came as Trump, the Republican presidential front-runner, has shrugged off attacks that he is a Democrat running on the GOP ticket. At the same time, Warren slammed Trump's attacks on illegal immigration, including his plan to deport 11 million immigrants.

"You can't be president of the United States if that's your view about how we're going to solve immigration reform," Warren said.

Warren, who has refused to run for president in 2016, has kept a close watch on the White House race. She also praised Sen. Bernie Sanders of Vermont for "generating an enormous amount of interest" during her TV appearance. But she stopped there despite calls for her to enter the race herself.

"This isn't about me," Warren said when asked about her White House ambitions. "I'm going to be out there talking about what I believe in, no matter what."

"View" co-host Joy Behar wasn't satisfied with that answer, calling Warren "presidential material." "I wish that you would run," Behar told the senator. Warren is serving her first term as a U.S. senator. She's up for re-election in 2018.

A Monmouth University poll released Tuesday had Hillary Clinton with 42 percent of Democratic support, a 18-point drop since April. Sanders' popularity, meanwhile, was on the rise.

Trump said in August that hedge funders should pay higher tax rates. "They're making a fortune, and I want to take care of the middle class," Trump said at the time. "We had a tremendous rally in Alabama and people came up and they said, 'You know, you're treating us fairly. The hedge-fund guys are paying nothing.' They're paying nothing."