Story highlights The Senate vote on Tillerson is scheduled for 4:30 p.m. ET.

Cardin also noted a number of his Democratic colleagues have shared similar views on the nomination.

Washington (CNN) Sen. Ben Cardin, D-Maryland, said he does not support Donald Trump's secretary of state pick, Rex Tillerson, hours before a Senate committee is set to vote on his confirmation, citing Tillerson's potential conflicts of interest and his position regarding Russian aggression.

"I will not be supporting his confirmation for secretary of state," Cardin said on CNN's "New Day." "During the confirmation hearings he raised me many questions as to whether his business interests would compromise his ability to speak out for US leadership on human rights and good governance."

Cardin also noted a number of his Democratic colleagues have shared similar views on the nomination.

"I think many members are troubled by the fact that Mr. Tillerson refused to comment as to whether Russia's activities should be considered war crimes -- what they've done in Aleppo. Or what happened with extra judicial killings in the Philippines is a violation of human rights," Cardin said.

.@SenatorCardin explains why he is not voting for Rex Tillerson & his concerns about Mike Pompeo. https://t.co/vcWt3mjhSe — New Day (@NewDay) January 23, 2017

Tillerson was considered by some a controversial choice because of his ties to big business and Russia. The former ExxonMobil CEO was awarded Russia's Order of Friendship in 2013.

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