Jordan has carried out unspecified air attacks, likely against the militant group ISIS. Above, a plane belonging to the Jordanian Royal Air Force flies over the headquarters of the family clan of pilot Muath al-Kasaesbeh in the city of Karak Feb. 4, 2015. REUTERS/Muhammad Hamed

The Jordanian Air Force has carried out an unspecified combat mission, Jordanian media reported Thursday. Jordan's King Abdullah II as well as the head of the country's army earlier this week swore revenge against the militant Islamic State group for its execution of Jordanian pilot Moaz al-Kaseasbeh, news of which emerged Tuesday.

"Official TV says that Jordanian fighters have returned to Jordanian airspace after carrying out a mission, without mentioning details," tweeted Al Rai, one of the country's major newspapers, in Arabic on Thursday above an image of a Jordanian fighter jet.

A brief statement on the Jordan Armed Forces website confirmed that Royal Air Force fighters were returning to Jordan after carrying out a mission. The Jordan Times suggested the mission had targeted the so-called Islamic State (aka ISIS) in Raqqa, Syria, the terrorist group's de facto capital. On Wednesday, Jordan launched airstrikes against ISIS in Iraq, killing 55.

Upon their return, the jets flew above Amman, Jordan's capital, and Karak, a southern governorate that was the hometown of Muath al-Kaseasbeh, the executed pilot. On Twitter, residents reported seeing and hearing the planes flying low in Amman. Official information about what the mission was or where it occurred had not been released by the time of this report.

Kaseasbeh was captured by ISIS in December after his F-16 crashed near Raqqa. Media reports suggest the 26-year-old was burned alive on Jan. 3. In response, "the revenge will be as big as the calamity that has hit Jordan," Colonel Mamdouh al-Ameri, a spokeman for the army, said.

On Wednesday, Washington Post reporters tweeted that Jordanian government officials and lawmakers hinted that putting Jordanian boots on the ground in Syria could be a "next logical step" in Jordan's retaliation against ISIS. In Syria, a civil war between government forces and various anti-government groups has been going on for more than three years.