Yemen government oil revenue came in at $1.1bn for the first seven months of this year, a 30 per cent decline from the $1.6bn it made during the same period in 2013, according to state-run Saba News Agency, which cited a report released by the Central Bank of Yemen.

The decline in oil revenues comes after repeated attacks on oil infrastructure from armed groups, and as political tensions mount in the capital, Sanaa.

The drop is a significant blow to the country, which relies on oil for about 70 per cent of the government’s revenue, according to CIA data.

There have been frequent pipeline attacks in recent months, including an attack on the country’s main export pipeline that runs to the Red Sea from the central oil-producing province of Maarib.

On 10 September, it was patched after saboteurs damaged a section in a bomb attack on 8 September, halting flows.

The pipeline was also attacked by tribesmen on 12 July. Tribesmen have allegedly been using the threat of attacks to push for jobs and other benefits from the government.