The president is expected to sign the first actions — including the measure to jumpstart construction of the wall — during a trip to the Department of Homeland Security. Additional actions will be rolled out over the next few days, according to one official.
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 United States, except for religious minorities escaping persecution, until more aggressive vetting is in place.
Another order will block visas being issued to anyone from Syria, Iraq, Iran, Libya, Somalia, Sudan and Yemen, said the aides and experts, who asked not to be identified.
The current proposal includes at least a four-month halt on all refugee admissions, as well as temporary ban on people coming from some Muslim majority countries, according to a representative of a public policy organization that monitors refugee issues. The person was briefed on the details of that proposed action by a government official.
In his tweet late on Tuesday, Trump said: "Big day planned on NATIONAL SECURITY tomorrow. Among many other things, we will build the wall!"
The border security measures probably include directing the construction of a border wall with Mexico and other actions to cut the number of illegal immigrants living in the United States.
The sources say the first of the orders will be signed on Wednesday. With Trump considering measures to tighten border security, he could turn his attention to the refugee issue later this week.