Washington - US rights groups on Monday pledged to keep fighting the new, open-ended version of President Donald Trump's controversial travel restrictions, insisting they remain a disguised Muslim ban.Despite the removal of Sudan from the block on travelers from six mainly-Muslim countries, and the addition of Chad, Venezuela and North Korea to the list, activists and legal experts said Trump's intent remained the same, to sharply cut off the flow of Muslim visitors and immigrants into the United States.READ MORE: New US travel ban targets 8 countries, as Sudan given reprieve"This ban is not any better than the previous one," said Zahra Billoo of the Council on American-Islamic Relations."The fact that Trump has added North Korea - with few visitors to the US - and a few government officials from Venezuela doesn't obfuscate the real fact that the administration's order is still a Muslim ban," said Anthony Romero, executive director of the American Civil Liberties Union. "President Trump's original sin of targeting Muslims cannot be cured by throwing other countries onto his enemies list."Open-ended banOn Sunday, the White House issued a new executive order to replace the expiring 90-day temporary ban on travelers from Sudan, Syria, Yemen, Iran, Somalia and Libya.The White House says the ban is necessary to prevent potential terrorists from entering the United States. The eight countries covered in the new order were chosen based on a Department of Homeland Security review of their immigration vetting and security cooperation, officials said.The new list places full bans on travelers from North Korea, Chad, Syria, Yemen, and Libya. For Iran, an exception to a full ban was made for students and exchange visitors.For Somalia, new immigrants are blocked but visitor visas will be allowed for business, official and personal reasons, though subject to tougher vetting. With Venezuela, officials from certain key ministries and government agencies, and their families, are banned.The new ban came after Trump fought for five months to get the temporary ban in place. Immigration advocates were able to block its implementation repeatedly on the grounds that it illegally singled out Muslims, as Trump had promised to do during his election campaign.After it was watered down, the Supreme Court allowed its implementation at the end of June, together with a 120-day ban on refugees. Meanwhile the highest court agreed to review whether it amounted to an unconstitutional Muslim ban on October 10.But, in a sign that the new order could shape the way the issue is addressed, possibly even mooting the case, the Supreme Court on Monday postponed the hearing to be able to review new arguments.A senior government official told reporters on Sunday that the new order, with two non-Muslim countries included, could not be construed as a Muslim ban."Religion, or the religious origin of individuals or nations, was not a factor," he said."The inclusion of those countries, Venezuela and North Korea, was about the fact that those governments are simply not compliant with our basic security requirements."'Rewriting the law'But critics called that "window dressing." One noted there were only eight visitors last year from North Korea, which does not have diplomatic relations with the United States.Adding Chad, North Korea and Venezuelan government officials "does little to undercut the argument that the government is imposing a ban based on religion," said Carl Tobias of the University of Richmond School of Law.In addition, lawyers say Trump has over-extended his executive powers on placing limits on immigration."He's basically rewriting the immigration law, entirely," said Justin Cox, an attorney at the National Immigration Law Center and one of the lawyers making the arguments against the travel ban at the Supreme Court."If he can indefinitely ban people from these countries, he can indefinitely ban guest workers, he can indefinitely ban Mexicans, do basically whatever he wants," Cox said.