WASHINGTON • The United States House of Representatives, defying a veto threat by President Barack Obama, has overwhelmingly passed Republican-backed legislation to intensify security screenings of Syrian refugees and suspend Mr Obama's programme to admit 10,000 of them in the next year.

The measure, introduced this week following the Islamic State in Iraq and Syria (ISIS) attacks in Paris on Nov 13 that killed 129 people, was approved on a vote of 289 to 137, with 47 of Mr Obama's 188 fellow Democrats breaking with the White House to support the Bill.

Meanwhile, countries along the migrant route through the Balkans have also begun tightening restrictions by accepting only those fleeing war, causing a backlog of hundreds of people on Thursday on the Greek-Macedonian border.

"Croatia is accepting migrants from only war-affected countries such as Syria, Iraq and Afghanistan," a Croatian police spokesman said. "Croatia informed other countries that so-called economic migrants will not be able to pass through the so-called Balkans route," she said. Similar statements were made by Serbia and Macedonia.

The vote in Washington came amid fears that some refugees could be militants.

The measure now goes to the US Senate. Both Houses would have to muster a two-thirds majority to override a veto. Under the proposal, refugees from Syria or Iraq cannot enter the US until top-level security officials verify that they do not pose a threat.

REUTERS, AGENCE FRANCE- PRESSE