LONDON, July 21 (Reuters) - Northwest European gasoline refining margins eased by nearly $4 to $41.13 a barrel on Tuesday, as underlying crude futures rallied because of heightening concerns about fresh disruptions in key Middle East shipping routes.

• A total of 4,000 tons of Eurobob E5 barges traded on Argus, with ExxonMobil selling to Gunvor.

• A further 1,100 tons of Eurobob E10 barges traded, sold by TotalEnergies to MB Energy.

• Petroineos also sold an E5 barge to Trafigura in the Platts window.

• The Dangote refinery, Nigeria's largest, has been undergoing maintenance work since July 10 due to issues with a steam generator, commodities analytics firm Kpler said, reducing run-rates at its crude-processing and gasoline-producing units.

• Yemen's Iran-aligned Houthi militia told shipping companies not to load or discharge cargo at Saudi Arabian ports or they may be targeted, according to an email the group sent to companies.

• Two oil tankers loaded with Saudi crude for China and India made U-turns in the Red Sea on Tuesday, heading towards the Suez Canal rather than braving the Yemeni coast at the sea's mouth following a warning from Yemen's Iran-aligned Houthi militia.

• Shell restarted a 200,000-barrel-per-day crude unit at its Pernis oil refinery in the Netherlands on July 20 after a brief outage, an alert from consultancy Wood Mackenzie seen by Reuters showed. The unit was shut down alongside the 25,600-vacuum distillation unit on July 18, Woodmac said, adding that the unit remained offline.