Egyptian security forces seized four vehicles transporting unlicensed fuel in the northern Sinai, officials said Saturday. Security officials said the vehicles were carrying 1,640 liters of fuel in 82 tanks for sale on the black market. A driver was detained for investigation, they added. Last week, security forces confiscated a truck in the Sinai carrying 10 thousand liters of fuel headed to tunnels under the border with Gaza Strip, officials said. Egypt moved in February to shut down fuel deliveries to Gaza via the tunnel network -- used to bring goods into the blockaded coastal strip -- sparking a fuel shortage that caused widespread blackouts. Officials have already agreed to stave off the electricity blackouts by upgrading the sole power plant, a project due for completion this month.