WASHINGTON/CHICAGO (Reuters) - Boeing BA.N Chief Executive Dennis Muilenburg on Wednesday spurned repeated calls to step down by U.S. lawmakers and from the mother of a young woman who was a victim of one of two 737 MAX crashes that killed 346 people.

Boeing Chief Executive Dennis Muilenburg testifies before the House Transportation and Infrastructure Committee during a hearing on the grounded 737 MAX in the wake of deadly crashes, on Capitol Hill in Washington, U.S., October 30, 2019. REUTERS/Sarah Silbiger

When asked at separate points whether he had offered to resign or planned to submit a letter of resignation, Muilenburg answered: “No.”

Muilenburg endured hours of aggressive questions related to his knowledge of events that led up to the 737 MAX crashes in Indonesia and Ethiopia, triggering the plane’s worldwide grounding. He acknowledged that Boeing would have grounded the plane after the first crash of a Lion Air flight soon after taking off from Jakarta if the company knew then what it knows now.

“These accidents happened on my watch. I feel responsible to see this through,” said Muilenburg, who was stripped of his title as board chairman earlier this month.

That did not satisfy critics.

“You either truly didn’t realize you had a defective plane, which demonstrates gross incompetence and/or negligence. Or, you did know you had a defective plane, but still tried to push it to market, in which case it’s just clear corruption,” Representative Jesus Garcia of Illinois said.

“You’re the captain of this ship. Cultural negligence, incompetence or corruption starts at the top and it starts with you,” Garcia said, adding: “I think it’s time that you submitted your resignation, don’t you?”

Representative Debbie Jessika Mucarsel-Powell echoed the call for the CEO’s resignation.

“At some point you have to take full responsibility of the negligence of these two flights,” Mucarsel-Powell said. “Mr. Muilenburg if you had an ounce of integrity you would know that the right thing to do is set to step down.”

Representative Paul Mitchell, a former CEO of a small company, told Muilenburg that he would have submitted his resignation under these circumstances “because I am responsible.”

Muilenburg repeatedly accepted accountability for the crashes but said he was driven by childhood values instilled growing up on a farm in Iowa to see the world’s largest planemaker through one of its worst crises. His repeating that answer drew jeers from family members in the gallery.

Nadia Milleron, the mother of Samya Stumo who was killed in the Ethiopian Airlines crash in March, approached Muilenburg after the hearing and demanded Boeing carefully ensure the 737 MAX is safe to fly, and then asked him to resign.

“You talked about Iowa just one too many times and the whole group said, ‘Go back to the farm, go back to Iowa’” Milleron told the CEO, adding, “Do that!”