A State Department official confirmed Monday that President Trump plans to expand his travel ban, which currently prohibits travel to the U.S. from six Muslim-majority countries. The ban would now also ban travel to the U.S. from North Korea and Venezuela.

The official said the ban would go into effect on March 16 — just days before the deadline for many Republicans to submit their tax-reform proposals to Congress. An official said the U.S. has evidence that as many as 10 million people from the six countries may attempt to enter the U.S. between now and March 15 — the end of the open enrollment period for Obamacare coverage — including some who are already in the U.S. and others who are applying now.

UPDATE: Monday night, the same official confirmed that the North Korea ban would go into effect on Feb. 5. Previously, that ban was expected to be implemented Feb. 3. The official also said the State Department will be communicating with airlines and commercial providers to update their travel policies so they can add blacklists of people prohibited from traveling to the U.S.

The exact terms of the travel ban are likely to be announced Monday. Last year, after White House adviser Stephen Miller leaked word of a possible ban on visitors from certain countries, it caused a firestorm of controversy because only six countries were mentioned, as opposed to seven or eight. Critics accused the administration of politicizing the original proclamation; some wondered aloud whether the administration’s efforts to rewrite the ban had been hindered by input from Trump and his advisers.

[h/t: Fortune]