ST. PAUL — Gov. Mark Dayton declined to say Thursday whether he asked for the resignation of the former CEO of Minnesota’s health insurance exchange, adding that he ultimately feels responsible for the success or failure of the venture.

Dayton was asked several times at a news conference if he pushed for the exit of April Todd-Malmlov, who resigned Tuesday as executive director of MNsure. Dayton said he wouldn’t comment on his role but noted he had grown increasingly vocal in recent days about his concern with problems that continue to plague the exchange, even as coverage is set to kick in on Jan. 1.

“I apologize to those Minnesotans who have been seriously inconvenienced or are distraught by the failures of MNsure. It’s unacceptable,” Dayton said Thursday. “We’re going to do everything we can, around the clock, to correct that.”

MNsure’s board of directors, which Dayton appointed, has tapped Scott Leitz to replace Todd-Malmlov as the agency’s interim CEO. Board members were also reluctant to reveal details of Todd-Malmlov’s abrupt departure, which came after the revelation she had taken a nearly two-week vacation in late November as MNsure’s problems mounted: a bug-ridden website, long wait times at its toll-free helpline, and error-plagued information transmitted to insurance companies.

Dayton said he grew increasingly worried about MNsure starting in mid-November, at a time when issues with the federal health care exchange seemed to be getting ironed out even as MNsure’s problems seemed to be mounting.

Dayton praised the choice of Leitz, who had been an assistant state commissioner of human services overseeing Minnesota’s Medicaid program, to take over the effort to implement the federal health care changes in Minnesota.

Dayton said he doesn’t feel personally at fault for MNsure’s challenges but said he accepted the fact that Minnesota voters would judge him on how it performs in the coming weeks and months.

“Ultimately the buck stops here,” Dayton said.