By Patricia Zengerle

WASHINGTON, Jan 31 (Reuters) - After days of chaos at airports and confusion over details of President Donald Trump's immigration executive order, some of his fellow Republicans joined Democrats in saying Congress might need to consider legislation to address his new policies.

Republican Senator Bob Corker, chairman of the Senate Foreign Relations Committee, said it was too early to know all the implications of Trump's order banning travel into the United States by citizens of seven majority-Muslim nations, but lawmakers might eventually need to step in to modify it.

"Seriously, we still don't know all the implications of what happened. I don't think they (the Trump administration) know all the implications of what happened," he told reporters at the U.S. Capitol. "There may well need to be a legislative fix."

Under the executive order Trump released on Friday, travelers from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen may not enter the United States for at least 90 days while Homeland Security Secretary John Kelly and others determine whether there is enough information available to screen them.

Democrats in both the Senate and House of Representatives have introduced bills to rescind Trump's order, but those measures are not expected to go anywhere in the Republican-led Congress.

Senator John McCain, the Republican chairman of the Senate Armed Services Committee, has criticized the order, saying it could weaken U.S. counterterrorism efforts.

He blasted barring Iraqis who risked their lives to work as interpreters for U.S. forces, who have already undergone extensive screening. McCain and Democratic Senator Jeanne Shaheen led a push to pass legislation last year to provide visas to those Iraqis.

McCain said he thought Iraq should not be on Trump's list. He said it could invite retaliation by Baghdad and said that Iraq should not be lumped in with frequent U.S. nemesis Iran.

"There's no comparison. There's thousands of Americans fighting in Iraq as we speak. And what if the Iraqis decided, OK, we're not going to let all these contractors (working with U.S. forces) ... have visas to come into our country?" McCain asked.

Iraq's prime minister on Tuesday said the country would not retaliate to Trump's travel ban against Iraqi nationals because it did not want to lose Washington's cooperation in the war on Islamic State.

McCain said whether legislation was needed would depend on how the executive order was implemented over time.

"Let's see what they do," McCain said. "General Kelly today made some very significant changes to what was initially publicized. So let's see what they do."

(Reporting by Patricia Zengerle; Editing by Andrew Hay)