The Armenian Gull (Larus armenicus) is difficult to distinguish from the Caspian Gull (Larus cachinnans) which is also widespread in Israel.
However, in general the Armenian Gull has a rounder head, a shorter and thicker bill and often shows a black sub-terminal band at the end of its bill.
Caspian Gulls have a long and slender bill and often have a stand-up position showing their "full" breast.
The Armenian Gull can be distinguished from the Yellow-legged Gull by its dark eyes.
The Armenian Gull was ranked as a full species in 1998.

The Armenian Gull (Larus armenicus) breeds in eastern Turkey, Armenia, southern Georgia and northwestern Iran.
It is an abundant winter visitor and passage migrant in Israel, and is the commonest large gull in Israel.
Birds are seen throughout Israel in varying numbers almost year-round, peaking between late September and Mid-March.
Its main wintering range is in Israel and possibly Lebanon, Syria and Egypt (Mediterranean coast).
Another small population is wintering in Kuwait.

Peter Adriaens, a Belgian ecologist and expert on European Gulls, helped me identifying this species.

At the beach, Tel Aviv City Centre, Israel, 29 December 2019