Damascus: President Barack Obama admitted that the United States underestimated the threat posed by Islamic State fighters in Syria, as the US-led coalition pressed its air campaign against the jihadists on Monday.
Obama said Washington had also overestimated the effectiveness of the security forces in neighbouring Iraq, which it had trained and supplied but which collapsed across much of the Sunni Arab heartland north and west of Baghdad in the face of a lightning offensive led by IS in June.
As the US-led air campaign in Syria entered its seventh day, coalition strikes hit IS targets during the night, both in its Raqa province stronghold and in Aleppo province further west, a monitoring group said.
In neighbouring Iraq, US-led strikes destroyed two IS checkpoints near insurgent-held Fallujah on Sunday, the Pentagon said, as Iraqi troops fought off a jihadist assault on a strategic Euphrates Valley town downstream.
Speaking to CBS News, Obama admitted his administration had underestimated the opportunity that the three-and-a-half year-old Syrian civil war would provide for jihadist militants to regroup and stage a sudden comeback.
He said that former Al-Qaeda fighters driven from Iraq by US forces in the years before their withdrawal in 2011 with the support of Sunni Arab tribes had been able to regroup in Syria to form the even more dangerous IS.
"I think our head of the intelligence community, Jim Clapper, has acknowledged that they underestimated what had been taking place in Syria," Obama said, referring to his director of national intelligence.
Asked whether Washington has also overestimated the ability or will of Iraq`s US-trained military to fight the jihadists on its own, Obama said: "That`s true. That`s absolutely true."
The US president said that part of the solution would be for Syria and Iraq to resolve their domestic political crises.
An enduring solution, Obama said, would require "a change in how not just Iraq, but countries like Syria and some of the other countries in the region, think about what political accommodation means."
"The Iraqis have to be willing to fight. And they have to be willing to fight in a nonsectarian way -- Shia, Sunni, and Kurd -- alongside each other against this cancer in their midst."
Washington has said it will press on with "near continuous" strikes against IS in both Iraq and Syria with the support of its coalition allies.In Syria, the raids have increasingly targeted oil and other economic infrastructure that funds the jihadists as well as military targets.
During Sunday night, coalition warplanes hit targets around the IS-held town of Minbej, including a complex of grain silos and a mill that the Syrian Observatory for Human Rights said was being operated by civilians.
The group`s director Rami Abdel Rahman said there were initial reports of civilian casualties in the raid, but no confirmed toll.
The coalition also struck the entrance of the country`s main gas plant in the eastern city of Deir Ezzor in an apparent warning to IS militants to abandon the facility.
The plant feeds a key power station in regime-held Homs province and several provinces would be left without electricity if it stopped functioning, the Observatory said.
Earlier on Sunday, coalition strikes targeted four makeshift oil refineries near the Turkish border as part of an intensifying efforts to disrupt the jihadists` lucrative oil-pumping and smuggling operations.
"Initial indications are that they (the strikes) were successful," US Central Command said.
The swathe of territory that IS controls straddling northwestern Iraq and eastern Syria includes most of Syria`s main oilfields.
Experts say the jihadists were earning as much as $3 million (2.4 million euros) a day from black-market oil sales before the US-led air campaign began.
US warplanes began strikes against jihadist targets in Syria last Tuesday with the support of Arab allies, expanding an air campaign that Washington began in Iraq on August 8.
Several European governments have approved plans to join the air campaign in Iraq, including most recently Britain, and Turkish President Recep Tayyip Erdogan said on Sunday that Ankara "cannot stay" out of the fight.
The Turkish government was to send motions to parliament later Monday requesting the extension of mandates for military action in Iraq and Syria so Ankara can join the coalition against IS.
Lawmakers are to debate the motions on Thursday.