Five Jordanian intelligence agents were killed in an attack on their office in a Palestinian refugee camp north of the capital Amman on Monday, government spokesman Mohammed Momani said.
"The intelligence agency office in the Baqaa camp was the target of a cowardly attack shortly before 7:00 am (0400 GMT) today that left five agents dead," Momani said.
He said security forces were investigating who was responsible for the "terrorist attack" on the first day of the Muslim holy month of Ramadan.
Jordan has carried out air strikes against the Daesh terrorist group in both Iraq and Syria.
One of its pilots was captured by Daesh when his plane went down in Syria in December 2014. The terrorist group later released gruesome footage of him being burned alive.
Jordan has also opened up the Prince Hassan airbase, northeast of the capital, to other members of the US-led coalition taking part in the air war.
In March, Jordanian authorities announced they had foiled an IS plot to carry out attacks in the kingdom in an operation that led to the deaths of seven terrorists.