At least 20 people were killed last weekend in bombings in Nigeria. Though no group has claimed responsibility, the use of motorcycles, small improvised explosives and targeted gunfire in the attack bore the hallmarks of militant Islamic sect Boko Haram.
Achese Igwe, president of Nigerian oil workers' union Nupeng, said security in the country was a grave concern.
"We challenge the federal government to urgently address the increasing rate of insecurity and corruption in the oil and gas sector, else our union will have no other option but to call our members to withdraw their services," he was quoted by the Platts news service as saying.
The attack comes three days after two office buildings in Abuja and Kaduna belonging to This Day newspapers were attacked by suicide bombers, leaving six dead.
Nupeng members work at oil export terminals in Nigeria. Nigerian authorities have expressed concern about the safety of union members involved in the trucking of petroleum products.