Eagle Pass, Texas — Texas’ attorney general on Thursday forcefully rejected a request from the Biden administration to grant federal immigration officials full access to a park along the southern border that the state National Guard has sealed off with razor wire, fencing and soldiers.

For three weeks, the federal government and Texas have clashed over Shelby Park, a city-owned public park in the border town of Eagle Pass that was once a busy area for illegal crossings by migrants. Texas National Guard soldiers deployed by Gov. Greg Abbott took control of Shelby Park earlier in January and have since prevented Border Patrol agents from processing migrants in the area, which once served as a makeshift migrant holding site for the federal agency.

The Department of Homeland Security, which oversees the Border Patrol, had given Texas Attorney General Ken Paxton until Friday to say the state would relent and allow federal agents inside Shelby Park. On Friday, however, Paxton rebuffed that demand, saying Texas state officials would not allow DHS to turn the area into an “unofficial and unlawful port of entry.”

“Your request is hereby denied,” Paxton wrote in his letter.

Paxton pledged to continue “Texas’s efforts to protect its southern border against every effort by the Biden Administration to undermine the State’s constitutional right of self-defense.”

Inside Shelby Park, Texas guardsmen have been setting barriers to impede the passage of migrants hoping to cross into the U.S. illegally, and instructing them to return to Mexico across the Rio Grande. The Texas Department of Public Safety also recently started arresting some adult migrants who enter the park on state criminal trespassing charges. 

Abbott and other Texas officials have argued the state’s actions are designed to discourage migrants from entering the country illegally, faulting the federal government for not doing enough to deter unauthorized crossings. But the Biden administration said Texas is preventing Border Patrol agents from patrolling the Rio Grande, processing migrants and helping those who may be in distress.

Immigration enforcement is a federal responsibility. Texas state officials are not legally authorized nor trained to screen migrants for asylum, arrest them for immigration violations or deport them to a foreign country. However, Abbott signed a law last month that he hopes will allow Texas officials to arrest migrants on illegal entry state-level charges and force them to return to Mexico. The Justice Department is seeking to block that law before it takes effect in March.

The Supreme Court earlier this week allowed Border Patrol to cut the razor wire Texas has assembled near the riverbanks of the Rio Grande, pausing a lower court order that had barred the agency from doing so. The razor wire in Shelby Park has remained in place, however, since federal officials have not been granted full access to the area.

While the Supreme Court has not ruled on Texas’ seizure of Shelby Park, that dispute could also end up being litigated in federal court if the Biden administration sues the state over the matter.

While the White House has called his policies inhumane and counterproductive, Abbott has argued he is defending his state from an “invasion,” and his actions in Eagle Pass have received the support of other Republican governors across the country.

U.S. officials processed more than 302,000 migrants at and in between ports of entry along the southern border last month, an all-time high that shattered all previous records, according to official government data published Friday. Illegal border crossings have since plummeted, a trend U.S. officials have attributed to increased Mexican immigration enforcement and a historical lull after the holidays.

Camilo Montoya-Galvez

Camilo Montoya-Galvez is the immigration reporter at CBS News. Based in Washington, he covers immigration policy and politics.