AQAP tied to Yemeni oil pipeline attack SANAA, Yemen, April 11 (UPI) -- Armed militants struck an oil pipeline in the southern Yemeni province of Shabwa using rocket-propelled grenades, witnesses said. A Yemeni security official told China's official Xinhua news agency on condition of anonymity that an oil pipeline from Shabwa to ports on the Gulf of Aden was bombed. "An armed group fired more than three rocket-propelled grenades on the pipeline, setting it on fire for the second time in less than two weeks," witnesses told the news service. The security official said he suspected al-Qaida in the Arabian Peninsula was behind the attack. There were no reports of injuries. The attack comes amid heightened violence attributed to AQAP and separatists in the south of the country. Last week, the country's Interior Ministry warned that AQAP was planning attacks on Sanaa. At least 40 people allegedly tied to AQAP were killed Tuesday in the southern province of Abyan, the independent Yemen Post adds. Yemen relies on oil exports for more than 60 percent of its federal revenue. The sale of 3 million barrels of oil was approved for June, the country's official Saba news agency reports.