He said the courts were "making the job very difficult", and should take the blame if something happened.
The federal appeals court on Saturday rejected the Trump administration's request to reinstate the ban.
The ban, affecting people from seven mainly-Muslim countries, was blocked by a federal judge on Friday.
This means that Mr Trump's directive will remain suspended and visa holders Iraq, Syria, Iran, Libya, Somalia, Sudan and Yemen will be allowed to enter the US until the full case has been heard.
