There were no injuries, but the explosive damaged buildings and brought panic to the streets of Ashkelon on Friday after more than a year of relative calm.
The group, which has claimed a series of attacks, raised its flag after attacks on police Thursday.
Officials said that they were examining the hull of an oil tanker that was damaged as it traversed a waterway between Iran and the Arabian Peninsula.
The Educational Testing Service had halted registrations two weeks ago after its bank refused to continue processing payments from Iran in light of recent sanctions.
President Ali Abdullah Saleh offered to bring leaders of an armed rebel faction into Yemen’s political process.
Arab nations on Thursday backed the Palestinian president’s refusal to immediately restart direct talks with Israel despite heavy pressure from the United States.
Attorney General Eric H. Holder Jr. said during a visit to Cairo that he hoped an investigation into the death of a man in police custody last month would be carried out “in a transparent way.”
