CNN  — 

Unidentified gunmen killed nine Pakistani workers in the restive southeastern border region of Iran, Pakistani officials say, just over a week after Iran and Pakistan carried out military strikes on each other’s territory.

No group or individuals have taken responsibility for the attack, in the city of Saravan, according to Iran’s semi-official Mehr News Agency.

Pakistan’s Ambassador to Iran confirmed the incident in a post on social media.

“Deeply shocked by horrifying killing of 9 Pakistanis in Saravan,” said Muhammad Mudassir Tipi. “Embassy will extend full support to bereaved families.”

“We called upon [Iran] to extend full cooperation in the matter,” he added.

The Pakistani Ministry of Foreign Affairs condemned the attack, calling it “a horrifying and despicable incident.”

“We are in touch with Iranian authorities and have underscored the need to immediately investigate the incident and hold to account those involved in this heinous crime,” Foreign Ministry Spokesperson Mumtaz Zahra Baloch said in a statement.

“Such cowardly attacks cannot deter Pakistan from its determination to fight terrorism.”

Iran’s Ministry of Foreign Affairs “strongly condemned” the shooting attack, spokesman Nasser Kanani wrote in a Telegram post on Saturday.

Investigations are being carried out by relevant Iranian authorities, Kanani wrote, adding that Iran and Pakistan “will not allow the enemies to harm the fraternal relations of the two countries.”

No group or individual has taken responsibility for the attack, according to Iran’s semi-official Mehr News Agency.

Last week, Pakistan and Iran carried out tit-for-tat strikes on militants on each other’s soil in a major escalation of tension between the two sides.

The two countries share a volatile border, stretching about 900 kilometers (560 miles), with Pakistan’s Balochistan province on one side and Iran’s Sistan and Baluchestan province on the other.

Both nations have long fought militants in the restive Baloch region along the border.

Since the attacks the two side have made efforts to de-escalate with the foreign ministers from each country holding a call, in which Pakistan emphasised their “the close brotherly relations”.