WASHINGTON: President Barack Obama has not established a “specific end date” for US military strikes in Iraq, the White House said on Friday, explaining the situation will depend on the security situation in the country.

“The president has not laid out a specific end date,” White House spokesman Josh Earnest told reporters. Pentagon spokesman Rear Admiral John Kirby said on Twitter that US forces bombed the jihadis after artillery fire against Kurdish regional government forces defending their capital Arbil.

Two US jets hit a mobile artillery piece, he said. A Kurdish official said the strikes targeted the towns of Gwer and Makhmur, southeast of the autonomous Kurdish region.

The US operation began with air drops of food and water for thousands of people hiding from the militants in a barren northern mountain range.

Many people who have been cowering in the Sinjar mountains for five days in searing heat and with no supplies are Yazidis, a minority that follows a 4,000-year-old faith.

Lufthansa, Turkish Airlines and other airlines canceled flights to and from Irbil after the airstrikes.

The UN said it was “urgently preparing a humanitarian corridor.”

Obama said the strikes would be limited and it remained unclear how much of a game-changer they would be on the ground. Iraq’s military chief of staff told AFP he expected to see his forces and the peshmerga reclaim large tracts of land “in the coming hours.”

Many people in Baghdad were skeptical of Obama’s motives.

“He did nothing for three years but something happened to the Kurds and the Christians and he started talking about terrorism,” said Rashaad Khodhr Abbas, a retired civil servant. “Where were you all this time, Obama?”

Meanwhile, one of Iraq’s most influential Shiite clerics, Moqtada Sadr, claimed that the IS men were poised to attack Baghdad and he vowed to send his men to defend the capital. “There are terrorist groups that have completed their preparations for a breakthrough into Baghdad,” the cleric said.