The U.S.-led bombing of militant targets inside Syria has intensified as Pentagon officials acknowledge a military mission that could take years. On Tuesday, American and other coalition forces launched more than 200 strikes on Islamic State targets. Speaking from the White House, President Obama vowed to “take the fight” to ISIS.

President Obama: “Once again, it must be clear to anyone who would plot against America and try to do Americans harm that we will not tolerate safe havens for terrorists who threaten our people. 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 for the security of the country and the region and for the entire world.”

Later in the day, President Obama met with leaders of the Arab countries taking part in the strikes — Bahrain, Jordan, Saudi Arabia, the United Arab Emirates and Qatar — on the sidelines of a one-day U.N. climate summit in New York City.

President Obama: “I just want to say thank you to all of you. This is obviously not the end of an effort, but is rather a beginning. But I’m confident we’ve got a partnership that’s represented here that will be able to be successful.”

Despite talk of an international coalition, The New York Times reports the United States is carrying out the vast majority of airstrikes from its warplanes and naval carriers.