President Biden's Department of Homeland Security was made aware in July of the thousands of Haitian migrants headed to the southern border but refused to act, according to a report

"Customs and Border Protection, Immigration and Customs Enforcement, or ICE, and DHS' Office of Intelligence and Analysis all had information as far back as July that indicated that large groups of Haitians were making their way north from South and Central America to the U.S. border," NBC News reported. 

The network cited information gathered from three unidentified U.S. officials who claimed an investigation has been opened to find out why so many Haitian migrants arrived so quickly at once.

The report, which also claims DHS "acknowledged the failures internally," falls in line with a string of reports and criticism that DHS knew about a coming migrant surge but did not act sufficiently.

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Last month, Brandon Judd, head of the National Border Patrol Council, the labor union representing Border Patrol agents, told Fox News that border patrol officials had been warned to prepare for a large influx of migrants coming through Del Rio.

"They were warned that this bridge where these people are crossing — at this exact spot — there was an uptick in traffic, and the traffic continued to go up, and they were warned they needed to prepare, they needed to put operations in place to deal with a large influx of people and they didn’t," he said.

The report also stated that the U.S. officials said there was disagreement among many within the department on whether it would be inhumane to deport Haitians who were arriving at the border after the assassination of Haitian President Jovenel Moïse in early July and an earthquake that struck the Caribbean country in August.

"Ultimately, the Biden administration opted not to ramp up deportations, and it then halted all deportation flights to the impoverished island country shortly after the earthquake," NBC News reported. "By mid-September, seeing the large numbers massing in Del Rio, ICE restarted the flights, and it has now deported more than 7,200 migrants to Haiti."

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Last month, Secretary of Homeland Security Alejandro Mayorkas admitted that the vast majority of some 30,000 Haitian migrants who crossed the southern U.S. border in recent weeks have already been released into the United States and insisted that the Department was not prepared for "the rapidity of the increase that occurred."

While Haiti has recently been hit by political turmoil and natural disasters, critics also specifically blame the Biden administration's policies for the new crisis. They cite the rolling back of border protections like the Migrant Protection Protocols, the return of "catch-and-release," the decision to grant Temporary Protected Status (TPS) to Haitians already in the country and the reported cancelation of a number of deportation flights.

"The recent situation in Del Rio resulted from the unprecedented movement of large numbers of individuals who traveled to a single point of the border within a matter of days," a DHS spokesman said.

"The Department’s humanitarian and operational response was swift, immediately deploying personnel, basic services, food and drinking water, clothing, transportation, and medical resources." 

Fox News' Adam Shaw contributed to this article.