ISLAMABAD - Pakistan said Saturday that four of its soldiers were killed when a 'group of terrorists' from across the Iranian side of the border attacked a routine military patrol operating between the two countries.

The deadly cross-border raid took place in the remote Kech district in southwestern Baluchistan province abutting Iran, the Pakistani military said in a statement.

'Necessary contact with the Iranian side is being made for effective action against terrorists on the Iranian side and to prevent such incidents in the future,' the statement said, without providing further details.

FILE - Iran's national flag waves in Tehran, Iran, March 31, 2020.

The Iranian Embassy in Islamabad condemned the attack and expressed sympathy to the families of the slain soldiers.

'Terrorism is the common pain of the two countries and the two Muslim nations have sacrificed precious lives in the fight against this plague,' the Iranian Embassy said on Twitter.

'Undoubtedly, strengthening the joint cooperation between the two countries will prevent terrorist groups from achieving their sinister goals,' wrote the Iranian diplomatic mission.

Pakistani Prime Minister Shehbaz Sharif expressed "grief and sorrow over the martyrdom" of the security personnel in the terrorist attack, his office said in a statement.

FILE - Pakistan's Prime Minister Shehbaz Sharif speaks during the climate summit in Sharm el-Sheikh, Egypt, Nov. 8, 2022.

No group immediately took responsibility for Saturday's attack, the second incident this year in Baluchistan, where ethnic Baluch separatists routinely target Pakistani security forces.

In mid-January, four Pakistani troops were killed when a military convoy patrolling along the more than 900-kilometer border came under an insurgent attack from across the Iranian side.

The outlawed Baluchistan Liberation Army, or BLA, routinely takes credit for attacks on Pakistani security forces. Officials in Islamabad say the group has set up sanctuaries in border areas of Iran, charges Tehran rejects.

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The Global Terrorism Index, released in March by the Australia-based Institute for Economics and Peace, said that BLA was responsible for 36% of nearly 650 terror-related deaths in Pakistan in 2022, making it 'the fastest-growing terrorist group in the world.'

Pakistan, the United States, and Britain have designated the BLA as a terrorist organization.

Baluch insurgents claim to be fighting for the independence of Baluchistan, alleging extortion by the central government of the region's natural resources and discrimination against its ethnic Baluch population. Pakistani authorities reject the charges.

The sparsely populated province, which also shares a significant chunk of the country's nearly 2,600-kilometer border with Afghanistan, is at the center of a multi-billion-dollar infrastructure development project being funded by China in Pakistan under Beijing's global Belt and Road Initiative.