BEIRUT, Sept 24 (Reuters) - U.S.-led forces carried out at least 13 air strikes in Syria close to the Iraqi border on Wednesday, a second day of targeting Islamic State militants who have seized land on both sides of the frontier, a group that tracks the Syrian war said.
Rami Abdulrahman, who runs the Syrian Observatory for Human Rights, told Reuters the raids had hit the border town of Albu Kamal and surrounding areas.
The United States with Arab allies launched air strikes on Islamic State in Syria on Tuesday. A spokesman for the U.S. military said those strikes were "only the beginning."
Albu Kamal, on the main Euphrates River valley highway, is one of the most important border crossings between Iraq and Syria, along a frontier that Islamic State wants to erase after seizing territory both sides and declaring a caliphate.
It links Islamic State's de facto capital Raqqa in Syria with strategic front lines in western Iraq and militant-held territory down the Euphrates to the western and southern outskirts of Baghdad.
Depriving Islamic State of the ability to cross the border freely in the Euphrates Valley could be an early strategic objective of the U.S.-led coalition, which aims to defeat the group on both sides of the frontier.
Islamic State has exploited its ability to cross the border to score victories on both sides: fighters pouring in from Syria helped seize much of northern Iraq during a lightning advance in June, and weaponry they captured was then sent back to help the group secure more land in Syria.
The area around Albu Kamal has already been the focus of heavy bombing by U.S-led forces in the first day of their air campaign in eastern Syria. The Observatory said around 22 strikes hit the area on Tuesday.
"The people there, the activists, say they (the strikes) are probably the (international) coalition, not the regime," Abdulrahman said, referring to the Syrian government. "The strength of the explosions are greater. Like yesterday."
A militant Islamist fighter in the area said there had been at least nine strikes by "crusader forces" that had hit targets including in an industrial area. (Reporting by Tom Perry and Mariam Karouny, Writing by Sylvia Westall; Editing by Peter Graff)