Jordan sharply increased airstrikes against the Islamic State in Syria on Thursday in retaliation for the immolation of one of its pilots, as the United States sent additional Black Hawk helicopters to Erbil in northern Iraq to increase the number of aircraft and personnel on call to rescue downed pilots.

Jordanian officials said dozens of warplanes carried out strikes against militant targets in Syria, hitting ammunition depots and training camps. That number is a dramatic increase over the two to four missions that Jordan had launched at one time in the past against militant targets. American officials said the Jordanians had conducted 15 to 24 strikes.

Jordanian military officials said the stepped-up attacks represented only a first wave. A rare public announcement by the Jordanian military opened dramatically, saying: “This is just a beginning. You will know who the Jordanians are!” […]