Even before the Afghan crisis, Sistan-Baluchestan was the most sensitive of Iran's difficult border regions.

ECONOMIST: Iran and Afghanistan

The province of Sistan Baluchistan is one of the least developed and one of the poorest areas of Iran.

BBC: Iran's vulnerability to earthquakes

Residents of Mashkel have close ties with ethnic Balochs in Iran's Sistan province.

BBC: The remote corner of Pakistan flattened by an earthquake

The Iranian Seismological Center said the earthquake, which it put at magnitude 7.5, had struck Iran's Sistan and Baluchestan province.

CNN: SHARE THIS

Iran has blamed Jundallah for carrying out deadly bombings, abductions and targeted killings in the southeastern Sistan-Balochistan province, which borders Pakistan.

CNN: Iran executes militant group leader

When the earthquake struck this week, many people preferred to take their injured across the border to the city of Zahidan in Sistan province.

BBC: The remote corner of Pakistan flattened by an earthquake

Fariborz Rashedi, the head of emergency medicine in Sistan Baluchestan, told Fars News Agency that so far he had received reports of only three casualties in the area.

WSJ: Strong Quake Hits Southeastern Iran

Sistan Baluchestan's governor said the epicenter was in a remote and uninhabited area, some 28 miles from the closest town, and much of the damage was limited to a few collapsed walls.

WSJ: Strong Quake Hits Southeastern Iran

The governor of Sistan Baluchestan said the epicenter was in a remote and uninhabited area, some 45 kilometers (28 miles) away from the closest town, and much of the damage was limited to a few collapsed walls.

WSJ: Strong Quake Hits Southeastern Iran