He also promises to take additional steps to improve U.S. security.
Trump commented a day after a San Francisco-based U.S. appeals court refused to reinstate his temporary ban on travel to the U.S. by refugees and residents of seven mostly Muslim countries in the name of national security.
Speaking at a White House news conference with Japanese Prime Minister Shinzo Abe, Trump says the administration will continue to work the case through the court process.
He says he has "no doubt that we'll win" the case.
Trump says the administration will do whatever is necessary to keep the country safe