The Jordanian military said it had struck "terrorist organisations" in neighbouring Syria on Monday in retaliation for a deadly attack on a church last week, hours after authorities arrested three men they accused of the killings.
It said air force jets had "destroyed several terrorist positions" and killed and wounded "numerous members" of groups linked to the perpetrators of the church attack.
Syria's state news agency SANA, citing a local health official, said the strikes across Daraa province in the country's south had killed eight civilians, including women and children.
Syria's government said that Jordan did not coordinate with it before launching deadly strikes on the country's south.
A Syrian government statement carried by state news agency SANA said "no prior coordination with the Syrian side was carried out concerning the military operation" by Jordan.
It said that authorities were investigating the strikes and discussing them with Amman while stressing the need for joint security coordination in border areas.
SANA quoted Syria's foreign ministry as saying that it had informed Jordan of "our complete reservation regarding the conduct of operations inside Syrian territory without prior coordination".
"Communication and coordination" was underway with Jordan "to address the repercussions of this incident in a manner that preserves security and the sovereignty of Syrian territory", it said.
Syria also closed the Nassib border crossing with Jordan on Tuesday, suspending passenger and commercial traffic in both directions due to developments on the ground in Daraa province, the Syrian General Authority for Border Crossings and Customs said in a statement.
On Friday, gunmen killed nine people during a funeral service at the Greek Orthodox St George's Church in the village of Hammoud in Karak governorate, southern Jordan.
Karak is home to a significant Christian community in Muslim-majority Jordan, where Christians make up between two and three percent of the population.
Major General Abdullah al-Maaytah, Jordan's director of public security, on Monday named the three detained suspects as Hazza Zaidan Mohammed, Meshal Zaidan Mohammed and Ahmad Sami Hussein.
The trio, two of them brothers and the other related by marriage, were cornered at an abandoned house where they had barricaded themselves inside and opened fire on security forces.
"All three terrorists have been injured. They have been taken to hospital and are still receiving treatment," Maaytah told a press conference.
'We will show them'
One of the suspects was in critical condition, Jordan's state broadcaster Al-Mamlaka reported. It added that there were no casualties among the security forces.
"This country must remain an oasis of security and stability, and we affirm that Jordan will remain impervious to anyone who dares to challenge it," Maaytah said.
Under Jordanian law, murder is punishable by death by hanging.
A number of weapons and a large quantity of ammunition were seized from the three suspects, the Public Security Directorate said.
Jordan's King Abdullah II said in a post on X that security forces "chased them to the very end".
"We vowed the terrorists would not escape punishment, and no proponent of dark ideologies that divide Jordanians will be tolerated," he wrote.
Earlier, the king visited wounded victims of the church attack in a hospital, dressed in military fatigues and carrying a pistol on his hip.
"We will show them," he vowed.
Interior Minister Mazen al-Faraya told Al-Mamlaka on Monday that the attackers were all Jordanians and "had been holed up in a building in one of the villages near the site of the attack".
"There is no indication of any external contacts or collaboration with foreign parties," he said.
Government communications minister Mohammad al-Momani said, "we stand ready and will strike with an iron fist, without mercy or leniency, against anyone who attempts to undermine Jordan's security".
Attacks on houses of worship in Jordan are rare. In 2016, an attack in Karak targeted a security centre and police patrols, leaving 10 people dead.
On Friday, Prime Minister Jafar Hassan ordered a three-day period of national mourning for the victims of the church attack, with flags to be flown at half-mast over government and public institutions.
Eight of the nine victims were laid to rest on Sunday next to the church in a funeral that drew a huge crowd amid a large security presence, AFP images showed.
The ninth person, Mohammed al-Qasous, was buried in south Amman on Monday.