(CNN) -- Iran faces increased ethnic unrest in one of its southeastern provinces, mirroring similar trouble in neighboring Pakistan, U.S. diplomats in Azerbaijan reported in a cable disclosed by the website WikiLeaks this week.
A rail line connecting Iran and Pakistan "has recently been repeatedly subject to rocket attacks and other disruption" by tribes in Sistan-Balochistan province, a largely Sunni Muslim province of the majority-Shiite Islamic republic, according to a June 2009 cable from the U.S. Embassy in Baku. In addition, one source told U.S. diplomats, Tehran was "rife with rumors" that police were leaving their posts empty at night "due to the increased danger of attack."
The cable stated that several Iranian contacts -- "including apolitical businessmen" -- reported that a pair of bombings in the spring of 2009 "reflect a surge in Balochi violence in the border area and inside Pakistan that has been building steadily over several years."
It added, "According to one source, the Iranian security forces may be losing effective control over growing areas in the countryside."
The document is among the vast cache of U.S. State Department papers that WikiLeaks, a website known for leaking official secrets, began releasing Sunday to widespread condemnation from the United States and its allies.
The memo was written just weeks after a bombing in the provincial capital of Zahedan that left more than 20 people dead. Iran accused members of the Pakistan-based Sunni rebel group Jundullah of fomenting trouble on its side of the border and accused the United States and Saudi Arabia of funding the group.
But the cable cited another source who said the government of Iranian President Mahmoud Ahmadinejad aggravated the situation by harassing Sunnis and appointing a "stupid, brutal" ally as governor until 2008.
"He claimed that these practices, combined with high unemployment, perceived discrimination and few government services, has increased anger among Balochis, and identification of the central government as an 'enemy,'" the cable states.
Pakistan has struggled with similar unrest in its southwestern province of Balochistan, which borders Iran. The provincial capital of Quetta has been plagued by sectarian violence between Sunni and Shia Muslims, along with Baloch separatist militant groups who want political autonomy.