The failure of the Mosul Dam, located in northern Iraq, has been a concern for Iraqi and American officials for years.
But the meeting hosted by Samantha Power, U.S. ambassador to the United Nations, and Mohamed Alhakim, Iraqi's U.N. ambassador, highlighted the seriousness of inaction and called on the international community to pay attention to "urgently-needed repair work," Power said.
The Mosul Dam is a two-mile-long barrier that can hold back as much as 441 million cubic feet of water, according to Engineering News-Record, a construction industry website. If breached, 500,000 to 1.47 million Iraqis living in the flood path would be at serious risk, according to the readout of Wednesday's briefing.
"In the event of a breach, there is the potential in some places for a flood wave up to 14 meters high (45 feet) that could sweep up everything in its path, including people, cars, unexploded ordnance, waste and other hazardous materials," Power said.
In the event of a disaster, the flooding of Mosul, which has a population of over 600,000, would happen in less than four hours, according to a statement from Iraqi Prime Minister Haider al-Abadi in February.
After the meeting, Power tweeted a map of Baghdad -- some 275 miles away from the dam -- which shows that water could flood the city in 77 hours, resulting in its population of 7 million to "face choice to flee or risk being stranded by flood."
ISIS no longer controls dam
The dam drew the attention of the international community in the summer of 2014 when ISIS militants took control of it, provoking fears that it could be used as a weapon of war.
While ISIS no longer has a stronghold on the dam, repair work and structural enhancements need to continue on the dam, "to prevent a humanitarian catastrophe of epic proportions," Power said, adding that the U.N. emergency appeal for such efforts is only funded 8 percent.
Last week, the Iraqi government signed a contract with an Italian construction company to work on the dam, according to the Italian Foreign Ministry.
"The stakes are too high, and the potential consequences too devastating, for us not to confront this problem now," Power said.