Barack Obama says fight against Islamic State not America's alone

US President Barack Obama on Tuesday vowed to continue the fight against Islamic State fighters following the first U.S.-led airstrikes targeting the militant group in Syria, and pledged to build even more international support for the effort. "Once again, it must be clear to anyone who would plot against America and do Americans harm that we will not tolerate safe havens for terrorists who threaten our people," Obama said before leaving the White House for the United Nations in New York.

Obama said the strength of the coalition, now at more than 40 countries, including five Arab states that took part in Tuesday's air campaign, shows the fight against such militants is not America's alone. "America is proud to stand shoulder to shoulder with these nations on behalf of our common security," he said. "The strength of this coalition makes it clear to the world that this not America's fight alone."

Obama also said he would meet with Iraqi Prime Minister Haider al-Abadi and "friends and allies" at the United Nations to continue building support for the coalition. "The overall effort will take time. There will be challenges ahead but we're going to do what's necessary to take the fight to this terrorist group," Obama said, adding that the campaign is in line with the strategy he outlined earlier this month to combat Islamic State.

The air campaign opens a new front against militants by joining Syria's 3-year-old civil war. Bahrain, Jordan, Qatar, Saudi Arabia and the United Arab Emirates participated in or supported the strikes against Islamic State targets. U.S. officials have said persistent strikes will continue, although the pace and timing will vary. More details were expected when the Pentagon briefs reporters on Tuesday. Islamic State has vowed revenge in the wake of the strikes.