Former Colorado Gov. John Hickenlooper took a shot at his fellow 2020 Democrats, suggesting that his fundraising numbers were lower than theirs because they promised "free stuff" to voters.

"The bottom line is for a small campaign like us from a, you know -- Colorado's about 6 million or a little less than 6 million people -- it's harder to raise money because we don't, we're not promising free health care or, you know ... free tuition for everyone, to forgive student debt," he told MSNBC on Tuesday.

His comments came as leading Democratic candidates -- like Sens. Elizabeth Warren, D-Mass., and Bernie Sanders, I-Vt. -- pledged to expand government's involvement in health care and higher education.

Hickenlooper previously clashed with Sanders when he offered a speech denouncing Sanders' version of "Democratic socialism." He predicted that pushing socialism would help President Trump win re-election in 2020.

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During his Tuesday appearance on MSNBC, Hickenlooper refused to reveal how much his campaign made but said he didn't reach the $24 million figure that Indiana Mayor Pete Buttigieg had announced. He argued that it was harder to get small donors with his message which he described as "a picture of this country -- and what it could be in the future -- that could resonate with everyone."

He went on to say that ideas like Sanders' were difficult to implement. Hickenlooper again warned against giving the impression that his party was socialist and specifically called out the "Green New Deal."

As Democrats started competing for the 2020 presidential nomination, the party faced an internal debate over how progressive it should be. Rep. Alexandria Ocasio-Cortez, D-N.Y., appeared t knock frontrunner and former Vice President Joe Biden over what she saw as too moderate of an approach to environmental policy.

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Biden, along with Warren, later incorporated Ocasio-Cortez's Green New Deal in their proposed environmental plans. Former Rep. John Delaney similarly faced pushback from Ocasio-Cortez and others when he pushed back on the idea that Democrats should tout "Medicare for all" before the 2020 election.