King Abdullah II during a military training session in July. The Royal Hashemite Court/Instagram

Jordanian F-16s launched 20 airstrikes on Islamic State targets on Thursday following King Abdullah II's declaration to wage a "harsh" war against militants from the group, also known as ISIS or ISIL, after the brutal execution of captured Jordanian pilot Moaz al-Kasasbe.

Abdullah participating in a military special operations training exercises as Jump-Master. The Royal Hashemite Court/Instagram

King Abdullah II, a former commander of Jordan's special forces, pledged to hit the militants "hard in the very center of their strongholds," AP reports.

Abdullah with military officials during an exercise. The Royal Hashemite Court/Instagram

The Jordanian government has denied the king's physical involvement in any aerial attacks.

Abdullah observing a military exercise in November 2013. The Royal Hashemite Court/Instagram

Dubbed the "warrior king," Jordan's 53-year-old leader has clocked in 35 years of military service.

Abdullah at a military ceremony in Jordan. The Royal Hashemite Court/Instagram

According to the king's bio, he enrolled in the UK's Royal Military Academy at Sandhurst in 1980 and went on to become an elite Cobra attack helicopter pilot.

King Abdullah II pilots his helicopter while visiting different areas in his kingdom. The Royal Hashemite Court/Instagram

Abdullah laughing with troops after a meal in the field. The Royal Hashemite Court/Instagram Three years later he turned Jordan's small special forces unit into today's elite Special Operations Command (SOCOM), arguably the best operatives in the Middle East.

Abdullah speaking with soldiers after sharing a meal. The Royal Hashemite Court/Instagram Frequently training alongside US special forces, Jordan's units are approximately 14,000 strong and may further contribute to the fight against ISIS beyond Jordan's airstrikes.

Abdullah observing a military exercise. The Royal Hashemite Court/Instagram

Abdullah, the Supreme Commander of the Jordan Armed Forces, at a military exercise. The Royal Hashemite Court/Instagram Members of Congress have asked for an increase in military assistance to the kingdom, AP reports. The US is providing Jordan with $1 billion annually in military assistance.

King Abdullah II starts his day participating in a military special operations training exercises as Jump Master. The Royal Hashemite Court/Instagram The fight against ISIS lost a crucial partner, the United Arab Emirates, in December after the Jordanian pilot was captured, The New York Times reported.

The UAE demands that the Pentagon improve its search-and-rescue efforts in northern Iraq before it rejoins the coalition, The Times said, quoting unidentified US officials.