President Trump kicked off the first formal meeting of the Presidential Advisory Commission on Election Integrity on Wednesday by promising to extract voter data from states so far unwilling to provide it to the panel and questioning why those states have chosen to withhold the information.

"If any state does not want to share this information, one has to wonder what they're worried about," Trump said before the commission convened its meeting on Wednesday. "There's something, there always is."

Kansas Secretary of State Kris Kobach, the commission's co-chairman, has faced resistance from more than a dozen states in his efforts to collect data on registered voters for use in the administration's investigation.

"All of that information will be forthcoming," Trump said of the states that have so far rebuffed Kobach's request.

Trump instructed the bipartisan group of state officials and election experts gathered in a meeting near the White House on Wednesday to pursue facts about the nation's voting system without bias or preconceived conclusions.

"Every time voter fraud occurs, it cancels out the vote of a lawful citizen and undermines democracy. Can't let that happen," Trump said.

"This issue is very important to me because, throughout the campaign and even after, people would come up to me and express their concerns about voting inconsistencies and irregularities, which they saw," Trump added.

Trump's election commission has faced controversy in the weeks since Kobach asked all 50 states to provide detailed information about their registered voters — including partial Social Security numbers.

But even before Kobach's request, critics had questioned the justification for such a sweeping inquiry, and some had accused the president of creating a commission for the sole purpose of validating his claim that millions of illegal ballots cost him the popular vote in the 2016 race.

Vice President Mike Pence, chairman the commission, introduced Trump by promising to "perform a truly nonpartisan service" with the panel's investigation.

"President Trump knows that the integrity of our electoral system transcends party lines," Pence said.

The vice president said the group's mission is to "study the registration and voting processes used in federal elections."