U.S. President Donald Trump is expected to sign several executive orders on Wednesday restricting 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 multimonth ban on admissions from all countries until the State Department and the Department of Homeland Security can increase the intensity of the vetting process.