Republican presidential candidate Marco Rubio is greeted by supporters Wednesday as he arrives to speak to New Hampshire legislators at the Statehouse in Concord, N.H. (Jim Cole/ AP)

MANCHESTER, N.H. -- Three days after he declined to offer a detailed comment on the Flint, Mich., water crisis, Sen. Marco Rubio (R-Fla.) on Thursday called it a "tragic" development due to a "significant government breakdown."

"There was a significant government breakdown in terms of when they switched the power -- the water source to a lake that was known to be polluted and unfortunately now we have people that are facing this terrible situation with potential lead poisoning and all sorts of things," Rubio told reporters. "It's a very -- a systemic and ugly breakdown at the local and state level. The governor has acknowledged that."

Rubio said "there'll have to be accountability." He did not call for Michigan Gov. Rick Snyder (R) to resign.

Speaking to members of the media in Winterset, Iowa, Republican presidential candidate Donald Trump made brief comments about the water crisis in Flint, Mich. (Reuters)

"We'll have to look and see how those decisions were made, and people will have to be held accountable for that, because it's having real human repercussions," he said. "And what we'll figure out now moving forward is what can the federal government's role be in assisting people, for example children in particular, that might have been exposed to lead."

Asked in Iowa on Monday about the crisis, Rubio said he had not yet been briefed on the situation. “That’s not an issue that, right now, we've been focused on," the Detroit News reported.

Rubio on Thursday called the crisis "quite tragic."

Take a look at the key moments that led up to Flint, a city of 90,000, getting stuck with contaminated water. (Claritza Jimenez/The Washington Post)