Syria on Tuesday shut the Nassib border crossing with Jordan, its only passenger and commercial crossing with its southern neighbour, a day after Jordanian airstrikes hit southern Syria in retaliation for a deadly attack on a church in Jordan last week. Syria's border and customs authority said the crossing, known as Jaber on the Jordanian side, was being closed "due to the current circumstances", suspending all traffic in both directions.

Jordan said on Monday that its air force had struck what it described as militant hideouts in southern Syria, after determining that the attackers behind the October 23 church shooting in Karak governorate were linked to "terrorist groups" operating across the border. At least nine people were killed and dozens wounded in that attack, which Jordan's King Abdullah II had pledged to answer firmly.

Jordan's armed forces said the strikes were carried out in coordination with the Syrian government and had killed and wounded members of the groups targeted and destroyed their vehicles. Damascus, however, denied any coordination and said it had opened an investigation into the strikes, stressing the importance of joint field and security coordination in border areas.

Syrian officials reported civilian deaths from the strikes. State news agency SANA, quoting a health official in Daraa province, said five civilians, including women and children, were killed. Syria's civil defence service said its crews recovered the bodies of seven people from four sites in Daraa and Suwayda provinces, including a family of five killed when a tent was hit in the village of Al Tai, an 80-year-old man in Al Shayyah and a 60-year-old man in Shahba.

Earlier on Monday, Jordanian security forces arrested three suspects in the church attack in the village of Al-Jadeeda after a shootout lasting about three hours. The suspects, two brothers and their brother-in-law, sustained serious injuries, according to a Jordanian government source.

The closure of Nassib halts the only direct road link for people and goods between the two countries, and the dispute over whether the strikes were coordinated leaves the episode unresolved. Both governments now face pressure to restore border cooperation and to establish the facts of the strikes, even as Jordan continues its investigation into the church attack.