ATHENS, Jan 4 (Reuters) - Greece"s DEPA Commercial has signed a long-term gas supply deal with Russia"s Gazprom which offers more favourable terms, the gas utility said on Tuesday. The contract, which ends in 2026, follows months of negotiation with Gazprom. DEPA said it included "very competitive pricing" compared to current European gas prices from 2022 onwards. DEPA did not provide further detail. An official close to the matter said that the agreement stipulates that the gas price for DEPA is indexed to the benchmark Dutch TTF price by 80%, while the rest will indexed to the oil price for 2022. Gazprom will continue to supply DEPA with two billion cubic metres (bcm) of gas per year, the official added.