The diesel refining margin was at around $8.25 a barrel, its lowest since May 13.
A deeper contango and brimming land storage have increased expectations for diesel to be stored on tankers in the coming days, traders said.
Demand in northwest Europe remained weak, with little activity reported in the barge market as high storage levels limit buying capacity.
Most of the cargo activity was focused in the eastern Mediterranean.
The failed coup attempt in Turkey has not impacted trading activity in the country, according to traders.
Imports into the region remained high with several new tankers booked in recent days from the Middle East and Asia.
Around 2 million tonnes are expected to arrive in July from the East and an additional 1.5 million tonnes from the US Gulf Coast, according to traders.
GASOIL
Barges of 0.1 percent sulphur gasoil traded during the afternoon window at discounts of $12 a tonne discounts to August diesel futures, compared with $15 to $18 a tonne discounts on Friday.
No cargoes traded. * No barges of 50 ppm gasoil traded.
August Low Sulphur Gasoil futures were down $9.25 a tonne at $404 a tonne at 1545 GMT.
The August contract traded in a contango of $7 a tonne to the September contract, unchanged.
The diesel refining margin was at around $8.25 a barrel, down from $8.75 a barrel and its lowest since May 13.
DIESEL
Barges traded at discounts of $11.50-$13 a tonne fob ARA to August diesel futures, compared with $10-$12.25 a tonne discounts on Friday.
No cargoes traded.
JET FUEL
Litasco and KLM sold three barges to Shell at $23 a tonne fob ARA above the August diesel futures.
No cargoes traded.