Brazilian oil workers began a 72-hour strike on May 30 in a new blow to President Michel Temer following a nationwide trucker protest that has strangled Latin America’s largest economy for over a week.

The strike affecting several rigs, refineries, plants and ports is the latest challenge for state-led oil firm Petroleo Brasileiro SA (NYSE: PBR), whose shares have tumbled nearly 30% in two weeks over fears that political interference would unwind more investor-focused policies.

Late on May 29, Reuters reported that Temer was considering an overhaul of a market-based fuel pricing policy at Petrobras, which could provoke even more investor flight. Temer’s office said in a May 30 statement that he would preserve the policy.

The oil sector strike included workers on at least 20 oil rigs in the lucrative Campos basin of 46 operated by Petrobras, as the company is known, according to FUP, Brazil’s largest oil workers union. Petrobras said any disruption would not have an immediate major impact on its production or overall operations.

Brazil produces about 2.1 million barrels of oil per day, making it Latin America’s largest crude producer.

The oil strike was declared illegal by Brazil’s top labor court on May 29, after Petrobras argued it was about politics rather labor issues. FUP said it had not been informed of the ruling.

According to a source close to the company, Petrobras has a significant stock of fuel on hand, especially as a 10-day protest by truckers prevented significant amounts of fuel from leaving refineries.

However, the strike has raised the specter of protests spreading to more sectors as Brazilians vent frustration with an unpopular government and an uneven economic recovery.

The truckers’ highway blockades and resulting fuel shortages have already halted major industries and hammered exports of everything from beef and soybeans to coffee and cars.

FUP said on May 30 that workers did not show up at work at eight refineries stretching from Manaus in the Amazon to Rio de Janeiro in the southeast. They also walked off the job at plants handling lubricants, nitrogen and shale gas, as well as in the ports of Suape and Paranaguá.

“Initial information points to the workers having adhered to the strike at various locations,” FUP said in a statement. “The movement is continuing through the morning, when stoppages at other Petrobras units are expected.”

Unions representing oil workers said they were demanding the resignation of CEO Pedro Parente. They also want the end of a market-based fuel pricing policy and other changes at Petrobras since Temer took power in 2016.

Adding to turmoil at Petrobras, the firm said on May 30 that board member José Alberto de Paula Torres Lima had resigned, citing “personal reasons.” He was one of three board members recruited by an outside agency and added to the board in April in an effort to establish its independence.

Petrobras did not respond to questions about his departure.

FUP union leader José Maria Rangel said on May 29 the Temer government and Parente’s policies were delivering Petrobras up to foreign investors, while “the shipyards of Rio de Janeiro are closed” as unemployment remains near record levels.

Parente, on a May 29 conference call with analysts, said Petrobras was taking action so that any strike would have minimal or no impact on production and operations.

The separate 10-day trucker protest against diesel price hikes has left major cities running short on food, gasoline and medical supplies, despite significantly easing on May 29.

Officials warned it would take days to restore supply lines disrupted by the crippling stoppage that at its height saw over 1,000 roadblocks on highways across the country.

Moody’s Investor Service warned in an analyst note that it will take weeks for operations to return to normal in sectors from meatpackers and automakers to airlines and retail.

“Normalization of transportation conditions within the coming days would not pose significant credit problems for the rated companies’ credit metrics, although it would still likely weaken quarterly financial results,” the Moody’s analysts wrote.

“But a prolonged strike would create severe credit stress across all corporate sectors in Brazil.”

Temer’s political situation has grown so tenuous as Brazil barrels toward a general election in October that he was forced to bat away concerns that a coup could topple his government.

“There is zero chance of military intervention,” Temer told a small group of journalists during a roundtable at an investment conference in Sao Paulo. “What I see is a rejection both in the Defense Ministry and throughout the armed forces to any kind of military intervention.”