ROUGH CUT (NO REPORTER NARRATION)

U.S. and Arab strikes on militant targets in Syria overnight were 'only the beginning' of a coalition effort to weaken Islamic State and other extremists, the U.S. military said on Tuesday.

"I can tell you that last night's strikes were only the beginning," Rear Admiral John Kirby, a Pentagon spokesman, told reporters. He said the strikes had been 'very successful' and would continue.

Another military spokesman said that Arab nations, including Saudi Arabia, Jordan, Bahrain and the United Arab Emirates, took part in the second and third waves of attacks. Lieutenant General William Mayville Jr. said the Arab countries' actions ranged from combat air patrols to strikes on targets.

Separately, U.S. forces acting alone launched strikes in another area of Syria against an al Qaeda-linked group to "disrupt imminent attack" against U.S. and Western interests by "seasoned al Qaeda veterans", U.S. Central Command said.