A watchdog agency at the U.S. Department of Homeland Security said it is planning to review how President Donald Trump's immigration executive order to temporarily suspend travel from seven majority-Muslim nations was implemented.

The review of Friday's order was being planned "in response to congressional request and whistleblower and hotline complaints," the DHS's Office of Inspector General said in a statement late Wednesday.

The watchdog agency would also look at "DHS' adherence to court orders and allegations of individual misconduct on the part of DHS personnel," the statement said. "If circumstances warrant, the OIG will consider including other issues that may arise during the course of the review."

The order triggered widespread protests and caused confusion for travelers around the world.

It also spurred several legal challenges, in particular over the initial detention or barring from flights of legal permanent residents who hold U.S. green cards.

As policy, the DHS does not comment on OIG investigations.

In California, a federal judge in Los Angeles on Tuesday ruled that Trump's administration must allow immigrants with initial clearance for legal residency to enter the United States despite the ban.

Massachusetts, New York, Virginia and Washington state have also challenged the order.

The Trump administration has defended the order as critical to U.S. national security.

On Sunday, the Homeland Security Department said green card holders would be allowed on U.S.-bound planes and assessed upon arrival, after revised guidance from the White House that said they did not need a waiver to enter the United States.

The OIG statement said it would provide a final report to Homeland Security Secretary John Kelly Congress and the public after its review but didn't say how long the review would take.