But a spokesman for Cameron's Downing Street office said Britain, which joined the US-led invasion of Iraq in 2003, was not planning its own military intervention.

"I am extremely concerned by the appalling situation in Iraq and the desperate situation facing hundreds of thousands of Iraqis," Cameron said in a statement.

"And I utterly condemn the barbaric attacks being waged by ISIL terrorists across the region."

He added: "I welcome President Obama's decision to accept the Iraqi government's request for help and to conduct targeted US airstrikes, if necessary, to help Iraqi forces as they fight back against ISIL terrorists to free the civilians trapped on Mount Sinjar”.

"And I fully agree with the president that we should stand up for the values we believe in - the right to freedom and dignity, whatever your religious beliefs."

However, a Downing Street spokeswoman said, "We are not planning a military intervention."

On June 10, the ISIL militants took control of Mosul, the capital of Nineveh Province, before the fall of Tikrit, located 140 kilometers (87 miles) northwest of the capital, Baghdad.

The terrorist group has been expanding its activities by occupying more areas in north of Iraq without facing any international confrontation.

Iraqi Prime Minister Nouri al-Maliki has said that the country’s security forces would confront the terrorists, calling the seizure of Mosul a “conspiracy.”

Maliki has blamed Saudi Arabia and Qatar for the security crisis and growing terrorism in his country, denouncing Riyadh as a major supporter of global terrorism.

SHI/SHI