President Donald Trump is reportedly expected to sign several executive orders on Wednesday banning immigrants from predominantly Muslim countries that are believed to play host to significant elements of Islamist terrorism.
The new Trump directives will reportedly restrict immigration from Syria and six other Middle Eastern or African countries, according to several congressional aides and immigration experts briefed on the matter.
In addition to Syria, Trump's orders are expected to temporarily restrict access to the United States for most refugees.
Another order will block visas from being issued to Iraq, Iran, Libya, Somalia, Sudan and Yemen, said the aides and experts, who asked not to be identified.
Trump's restrictions on refugees are likely to include a multi-month ban on admissions from all countries until the State Department and the Department of Homeland Security can increase the intensity of the vetting process.
The Republican president was expected to sign the orders at the Washington headquarters of the Department of Homeland Security, whose responsibilities include immigration and border security.
On the campaign trail, Trump initially proposed a temporary ban on Muslims entering the United States to protect Americans from jihadist attacks.
Many Trump supporters decried Democratic 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.
Both Trump and his nominee for attorney general, US Senator Jeff Sessions, have since said they would focus the restrictions on countries whose emigres could pose a threat rather than placing a ban on people who follow a specific religion.
To block entry from the designated countries, Trump is likely to instruct the US State Department to stop issuing visas to people from those nations, according to sources familiar with the visa process.
He could also instruct US Customs and Border Protection to stop any current visa holders from those countries from entering the United States.
White House spokesman Sean Spicer said on Tuesday that the State and Homeland Security departments would work on the vetting process once Trump's nominee to head the State Department, Rex Tillerson, is installed.
Other measures may include directing all agencies to finish work on a biometric identification system for non-citizens entering and exiting the United States and a crackdown on immigrants fraudulently receiving government benefits, according to the congressional aides and immigration experts.
To restrict illegal immigration, Trump has promised to build a wall on the US-Mexico border and to deport illegal migrants living inside the United States.
None of the orders to be signed Wednesday are expected to focus on those issues.
Trump is also expected to swear in his new secretary of homeland security, retired Marine General John Kelly, on Wednesday.