US President Barack Obama on Wednesday demanded the world take action against the "cancer" of "jihadist" extremism in Iraq, after militants murdered an American reporter.

US President Barack Obama on Wednesday demanded the world take action against the "cancer" of "jihadist" extremism in Iraq, after militants murdered an American reporter.

As US jets continued to strike jihadist targets despite a threat to kill a second reporter, Obama said: "When people harm Americans anywhere, we do what's necessary to see that justice is done."

Shortly after he spoke, the State Department asked for 300 more US troops to be sent to Iraq to protect US facilities.

Obama was speaking after the so-called "Islamic State," which has seized much of eastern Syria and northern Iraq, released a video showing a masked militant beheading US reporter James Foley.

US Weighs Sending up to 300 Troops to Iraq for Security
   
The United States is weighing sending up to 300 troops to Iraq to reinforce security at American diplomatic installations, a senior US official said Wednesday.

"We are considering sending fewer than 300," the official said, saying it was in response to a State Department request for additional security personnel.