Arizona Governor Katie Hobbs, a Democrat, has accused President Joe Biden of failing to secure the southern border, and is seeking half a billion dollars in federal reimbursement for the state's spending on the crisis.

In a letter on Friday, which Hobbs released publicly, the governor requested more than $512 million in federal funds to reimburse state spending on illegal alien transport, drug interdiction, and law enforcement 'due to the federal government's failure to secure our border.'

It comes after Customs and Border Protection encounters with illegal aliens at the southern border reportedly hit a one-day high of 12,000 on Tuesday, including more than 10,200 who were detained illegally entering the US from Mexico between ports of entry.

On Monday, CBP closed the Lukeville border crossing in Arizona indefinitely, in order to surge agents from the crossing to help arrest and process a flood of illegal aliens walking across the border to claim asylum.

The desolate area around the remote crossing has become a global illegal migration route in recent months, with smugglers dropping off illegal foreigners from countries as far flung as Senegal, India and China.

Most of them are walking into the US west of Lukeville through gaps in the wall, then turn east toward the official border crossing to surrender to the first agents they see to claim asylum, according to the AP.

Hobbs in her letter slammed the closing of the Lukeville crossing, saying it 'has led to an unmitigated humanitarian crisis in the area and has put Arizona's safety and commerce at risk.'

'Our ports of entry are essential to our state and our country's economy, and it is vial that they be properly staffed and resourced to continue to fuel economic growth in the state,' she added.

Hobbs called for National Guard members who are currently on active federal duty be mobilized to assist CBP in manning the Lukeville crossing, so it can be reopened.

The White House and CBP did not immediately respond to requests for comment from DailyMail.com on Saturday morning.

In a statement last week, CBP said it was 'surging all available resources to expeditiously and safely process illegal aliens' and will 'continue to prioritize our border security mission as necessary in response to this evolving situation.'

The agency blamed the hundreds of people arriving daily around Lukeville on 'smugglers peddling disinformation to prey on vulnerable foreign individuals.'

Alongside Governor Hobbs, Arizona Senators Mark Kelly and Kyrsten Sinema have slammed the Lukeville closure and demanded better solutions from Biden's administration.

'This is an an unacceptable outcome that further destabilizes our border, risks the safety of our communities, and damages our economy by disrupting trade and tourism,' they said in a joint statement.

Illegal foreign nationals line up at a remote U.S. Border Patrol processing center after crossing the U.S.-Mexico border on Thursday in Lukeville, Arizona. A surge of foreigners illegally passing through openings cut by smugglers in the border wall has overwhelmed U.S. immigration authorities, causing them to shut down several international ports of entry so that officers can help process the new arrivals. (Photo by John Moore/Getty Images)

'The Federal Government must act swiftly to maintain port of entry operations, get the border under control, keep Arizona communities safe, and ensure the humane treatment of illegal foreign nationals.'

Kelly and Hobbs, both Democrats, and Sinema, an independent who was elected as a Democrat, also criticized 'partisan politicians who parrot talking points while watching the border further deteriorate.'

They said those politicians should instead 'reject the echo chamber and work with us to get something done and keep our communities safe.'

An average of 3,140 people in vehicles and 184 pedestrians entered the U.S. daily in Lukeville during October, according to the U.S. Transportation Department´s latest figures.

Travelers will still be able to cross into or out of the United States through Nogales, Arizona, a three-hour drive to the east, or San Luis, Arizona, a two-hour drive to the west.

CBP has not commented on when the Lukeville crossing will reopen.