European Union member Hungary has maintained what it calls pragmatic relations with Moscow since Russia's invasion of Ukraine, creating tensions with some European Union allies keen to take a tougher line.
Hungary, which is about 85% dependent on Russian gas, firmly opposes the idea of any EU sanctions on Russian gas imports and Prime Minister Viktor Orban has also lobbied hard to secure an exemption from EU sanctions on Russian crude oil imports.
Foreign Minister Peter Szijjarto met his Russian counterpart Sergei Lavrov in Moscow last month, seeking a further 700 million cubic meters of gas on top of an existing long-term supply deal with Russia.
Under a subsequent agreement, Gazprom started ramping up gas flows to Hungary on Friday, Hungarian Foreign Ministry State Secretary Tamas Menczer said in a statement.
Menczer said Gazprom would add 2.6 million cubic metres of additional gas per day to previously-agreed deliveries via Turkstream through August, with the amount of September deliveries being negotiated.
Hungary's reserves stored 2.84 billion cubic metres of gas by the middle of July, the lowest level for that period over the past five years based on data by the national energy regulator.
Under a deal signed last year, before the start of the war in neighbouring Ukraine, Hungary receives 3.5 billion cubic metres (bcm) of gas per year via Bulgaria and Serbia under its long-term deal with Russia and a further 1 bcm via a pipeline from Austria.
The agreement with Gazprom is for 15 years, with an option to modify purchased quantities after 10 years.
(Reporting by Gergely Szakacs; Editing by Ros Russell)