New York and Washington state officials on Monday vowed to sue United States President Donald Trump if he scraps the Deferred Action for Childhood Arrivals, or Daca, programme. Daca protects individuals who came to the US illegally as children, who are often called “dreamers”, from deportation.

“The president’s action would upend the lives of hundreds of thousands of young people who have only ever called America their home,” New York Governor Andrew Cuomo said in a joint statement with the state’s attorney general, Eric Schneiderman, according to Reuters. The attorney general added that if Trump ended the programme, it would be “cruel, gratuitous, and devastating to tens of thousands of New Yorkers, and I will sue to protect them,” reported The Independent.

Bob Ferguson, the attorney general of Washington, also vowed to fight a legal battle if Trump scrapped the dreamers programme. “I will use all the legal tools at my disposal to defend the thousands of Dreamers in Washington state,” he said in a statement.

Ferguson and Schneiderman are among 20 attorneys general who wrote to Trump in July, saying if he ended the programme, they would “defend it by all means possible”. Apart from the attorneys general of New York and Washington state, nine attorneys general of Republican-ruled states have also threatened to sue Trump if he scraps the Daca programme.

Some leaders of the Republican Party, which Trump belongs to, have urged him not to scrap the programme. “I actually do not think he should do that. I believe that this is something that Congress has to fix,” Paul Ryan, speaker of the US House of Representatives said on radio station WCLO on Sunday. “At the end of the day, these kids do not know any other home. I think there is a humane way to fix this.” He added that he thought Trump agreed that it needs to be “fixed” and that it lies with the legislature to do it. “I think we need some time.”

Facing opposition from both the Republican and Democratic parties, the US president has decided to delay enforcement of his decision to end the Daca programme. The US Congress will now get six months to come up with an alternative programme.