Donald Trump has said there will be no deal to give legal status to migrants who came to the US as minors. In a series of tweets on Sunday, he also told Republicans to take the “nuclear option” and eliminate the Senate filibuster.

The US president began his tirade by claiming that catch-and-release laws are hindering efforts at border protection. Trump then attacked Mexico, saying the country was doing “very little, if not nothing” to stop migrants from other Central American countries from crossing its southern border on their way to the US. As punishment for their perceived inaction, Trump threatened to dismantle the North American Free Trade Agreement (NAFTA).

The billionaire property tycoon later claimed that “big flows” of people were trying to cross the border in time to take advantage of the Deferred Action for Childhood Arrivals (DACA) deal, a long-delayed piece of legislation designed to protect illegal immigrants who entered the country as children. “They want in on the act,” he wrote.

Catch and release was the system that allowed people who were caught for entering the country illegally to go free while they awaited a hearing by an immigration judge. The policy ended under President George W. Bush in 2006 and was replaced by a policy in which illegal immigrants were either detained or returned to their own countries.

Current Senate rules mandate that 60 senators – a near-two-thirds majority of the 100-member house – must agree in order to move forward to a vote on legislation. Trump has long called for an end to these rules, saying that he would like to see a simple 51-vote majority system.