Nigeria’s distributable revenues to the three tiers of government fell in July to around 444 billion naira after 559 billion naira in June as militant attacks hit oil revenues, the finance ministry said on Thursday.

Nigeria, Africa’s biggest economy and an OPEC member which relies on crude sales for about 70 percent of national income, has been hit hard by the fall in global crude prices since mid-2014.

Militants have carried out a series of attacks on oil facilities in the southern Niger Delta energy hub in the last few months, reducing oil output by 700,000 barrels a day, according to state oil firm NNPC.

“Crude oil export volume decreased… partly because of a subsisting force majeure declared at (Shell’s) Forcados Terminal,” said Mahmoud Isa-Dutse, permanent secretary of the ministry of finance.

“Also, shut-in and shut-down of pipelines at other terminals due to the activities of vandals and maintenance impacted negatively on production,” he said.

The distributable revenues includes value-added tax payments of 64.308 billion naira, the ministry said.