Arizona Attorney General Mark Brnovich is asking President Biden to return from his trip to Europe and address the massive migrant surge on the southern border after May numbers from Border Patrol indicate the number of migrants coming to the U.S. is much higher than it's been in years. 

"[Y]our administration revealed Border Patrol Agents along our Southwest border encountered more than 180,000 migrants in May alone," Brnovich said in a Thursday letter to the president. "Since the start of this fiscal year, nearly one million migrants have been apprehended, and we still have several months left."

May's migrant encounter numbers are up massively compared to 2020 and 2018, when just over 23,000 and 51,000 migrants crossed the border in May of those years. Even in 2019 when there was a migrant surge, Border Patrol encountered just over 144,000 migrants in May, the highest total of any month that year. 

Brnovich said that the crisis threatens the United States' "safety, security, environment, and economy" and is also a "humanitarian disaster" due to the dangers migrants encounter on their trek from Central America and through Mexico to get to the U.S.-Mexico border. 

MIGRANT ENCOUNTERS RISE ABOVE 180K IN MAY AS BORDER CRISIS CONTINUES

"Mr. President, the buck stops with you. You are the Commander in Chief and are responsible for the conditions at the border," Brnovich added. "I believe solving this crisis starts by visiting the border and talking to the members of law enforcement and land owners on the ground. I hope that you will join me at the southern border in Arizona in the near future. I will make myself available at a date and time of your choosing."

The letter from Brnovich comes as Biden is slated to remain in Europe until at least June 16, when he will meet with Russian President Vladimir Putin. In the meantime, Biden will also participate in summits with the United Kingdom, the G7, NATO and the European Union. 

Vice President Harris, meanwhile, recently finished a trip to Central America where she sought to address the "root causes" of the migrant surge, including, she said, corruption and economic squalor in Central America. 

In an interview with NBC News, Harris laughed at the idea of visiting the border, drawing harsh criticism from many on the right. Harris, who was tasked by the president with handing the border surge, later said that she will visit the border.

In this Tuesday, June 8, 2021, photo, a group of Brazilian migrants make their way around a gap in the U.S.-Mexico border in Yuma, Ariz., seeking asylum in the United States after crossing over from Mexico. (AP Photo/Eugene Garcia)

In this Tuesday, June 8, 2021, photo, a group of Brazilian migrants make their way around a gap in the U.S.-Mexico border in Yuma, Ariz., seeking asylum in the United States after crossing over from Mexico. (AP Photo/Eugene Garcia) (AP Photo/Eugene Garcia)

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"Yes, I will and I have before," Harris in response to a question about whether she would visit the border. 

White House press secretary Jen Psaki meanwhile said that Harris "may" visit the border "at some point." 

Republicans have hammered the Biden administration over the border, seeing it as a winning political issue as many migrants say they are coming to the Untied States due to a perception that the Biden administration would not enforce American immigration laws as strictly. 

Fox News' Adam Shaw and Brooke Singman contributed to this report.