(Adds industry source)
By Randy Fabi
ABUJA, Jan 28 (Reuters) - Heightened security measures at Nigeria's offshore oil terminals in the Niger Delta are delaying crude oil shipments from the world's eighth-largest exporter, a shipping agent and industry sources said on Wednesday.
The security measures, which restrict oil loading onto shipping vessels at the terminals to only daylight hours, were imposed at the beginning of the year amid a spike in attacks on oil services vessels.
Africa's top oil producer has one of the world's highest incidence of piracy, second only to Somalia, with 10 attacks reported so far this year.
"The loading time has doubled since you can only load during half of the day," said a shipping agent in Nigeria, who wished not to be named.
He said the terminals affected included Brass and Okwori in the Niger Delta, one of the world's largest wetlands and the heart of Nigeria's oil and gas operations.
The regulations meant at some terminals vessels being loaded were required to disconnect by 1800 hours (1700 GMT), drift a safe distance out to sea and return the following morning.
"There are tighter security operating measures going in as we speak," one industry source told Reuters, adding that loading in daylight hours was one of the steps being taken.
"The industry as a whole is looking at enhanced security at oil installations generally and export terminals specifically in Nigeria," the source said.
Violence in the Niger Delta has cut a fifth of the OPEC member's oil output in the last three years. Nigeria is currently pumping around 2 million barrels of crude per day (bpd), according to Oil Minister Rilwanu Lukman.
Gunmen attacked an oil tanker at the Bonny crude oil loading platform last week before attacking at least one other vessel and kidnapping several crew members.
In another incident last week, gunmen in speedboats used dynamite to attack a tanker loaded with 4,000 tonnes of diesel at the Bonny Fairway Buoy in the delta.
The president of oil workers' union PENGASSAN was quoted on Wednesday as saying the workers' body may pull its members off oil rigs in the Niger Delta in protest at a lack of aerial surveillance by the country's air force.
He said naval patrols alone were not enough to meet the security threat in the region. (Additional reporting by Nick Tattersall; editing by Nick Tattersall and James Jukwey)