The bodies of nine Pakistani laborers killed by gunmen in Iran last week were repatriated to their home country Thursday.

It was still unclear who was behind the attack Saturday in a home in Iran’s Sistan and Baluchestan province. Three Pakistanis wounded in the attack were still being treated at an Iranian hospital.

Read: 5 killed as blast hits political rally in SW Pakistan

Tehran handed over the bodies of the slain men at the Taftan border crossing, local government administrator Waqar Kakar said. He said the bodies were being flown to the city of Multan and will be sent from there to their hometowns.

The killings occurred as tensions erupted between Pakistan and Iran after Pakistan launched retaliatory strikes inside Iran that were said to be targeting militant hideouts and killed at least nine people. An Iranian attack against alleged militant hideouts inside Pakistan killed two children in southwestern Baluchistan province.

Read: Pakistan launches retaliatory airstrikes on Iran

Following the tit-for-tat attacks, both sides agreed Monday to improve their security cooperation.

The attacks appeared to target two Baluch militant groups with similar separatist goals. The two countries have accused each other of providing safe haven to the groups in their respective territories.