The U.S. government has granted waivers to let 872 refugees into the country this week, despite President Donald Trump's executive order on Friday temporarily banning entry of refugees from any country, according to an internal Department of Homeland Security document seen by Reuters.

A Homeland Security official, speaking on condition of anonymity, confirmed the waivers, noting that the refugees were considered "in transit" and had already been cleared for resettlement before the ban took effect.

Refugees preparing for resettlement typically have severed personal ties and relinquished their possessions, leaving them particularly vulnerable if their plans to depart are suddenly cancelled.

The waivers, granted by the State Department and the Department of Homeland Security (DHS), came amid international protests against Trump's rushed executive order. Critics said the order in some cases was not clearly communicated to the agencies responsible for implementing it.

It was not known if additional waivers would be granted, the official said. The document did not give the nationalities of the refugees who will be admitted into the United States.

Over the weekend, non-refugee visitors from seven majority-Muslim countries also targeted in Trump's executive order were detained, deported and in some cases blocked from boarding flights to the United States.

The countries covered by the traveller ban were Iran, Iraq, Syria, Sudan, Somalia, Libya and Yemen.

The internal DHS document said that between late Friday and early Monday 348 visa holders were prevented from boarding U.S.-bound flights. In addition, more than 200 people landed in the United States but were denied entry, the document showed.

More than 735 people were pulled aside for questioning by U.S. Customs and Border Protection officers in airports, including 394 legal permanent U.S. residents holding green cards, over the same time period.

Trump said the executive order he signed on Friday was designed to protect the United States "from foreign terrorist entry."

The order stopped all refugee admissions for 120 days while government officials determine how to ensure that any refugees admitted do not pose a threat.

The 872 refugees to be admitted this week, under the waivers, were screened using Obama administration procedures, which typically take two years and include several interviews and a background check.

The DHS said on Sunday night that green card holders would be allowed to board U.S.-bound flights, but would be subjected to additional scrutiny upon arrival.

The public guidance from DHS also said some people from the seven majority-Muslim countries could be allowed entry to the United States on a case-by-case basis.

Congressional Democrats and some foreign countries, including key U.S. allies, put pressure on Trump on Monday over the executive order.

Democratic Senators tried to force a vote on a bill to rescind the order, but were blocked by a Republican lawmaker. Democratic Senator Dianne Feinstein said she had 27 co-sponsors for the legislation. But under Senate rules it takes only one member to prevent a vote, and Republican Senator Tom Cotton blocked consideration of the measure.

The Democrats' leader in the U.S. Senate, Chuck Schumer, said he would bring legislation on Monday evening seeking to end the ban, although the measure stood little chance of being passed by the Republican-led Congress.