Donald Trump is expected to launch a raft of "national security" measures on Wednesday, including a temporary ban on refugees and an announcement on his Mexico wall pledge.
The new US President expected to sign executive orders that include a suspension of visas for citizens of Syria and six other Middle Eastern and African countries
He also signalled that work would begin on building a dividing wall between Mexico and the Unites States.
Mr Trump, who tweeted that a "big day" was planned on national security on Wednesday, is expected to ban for several months the entry of refugees into the US.
An exception could be made for religious minorities escaping persecution, until more aggressive vetting is in place.
Another order is predicted to block visas being issued to anyone from Syria, Iraq, Iran, Libya, Somalia, Sudan and Yemen.
In his tweet late on Tuesday, Mr Trump said: "Big day planned on NATIONAL SECURITY tomorrow.
“Among many other things, we will build the wall!"
The border security measures include directing the controversial construction of a wall with Mexico and other actions to cut the number of illegal immigrants living in the US.
Mr Trump, who took office last Friday, was expected to sign the first of the orders at the Department of Homeland Security, whose responsibilities include immigration and border security.
On the campaign trail, he initially proposed a temporary ban on Muslims entering the US, which he said would protect Americans from jihadist attacks.
Both Trump and his nominee for attorney general, Senator Jeff Sessions, have since said they would focus the restrictions on countries whose migrants could pose a threat, rather than a ban on those of a specific religion.
Many Trump supporters decried former President Barack Obama's decision to increase the number of Syrian refugees admitted to the United States over fears that those fleeing the country's civil war would carry out attacks.
