Brazil has collected more than 600 tonnes of oil from its northeastern beaches since Sept. 12, the country’s government said — more than double an estimate of oil and sand collected by state-run oil company Petrobras.

The crude has washed up on at least 200 beaches in nine Brazilian states and is threatening marine life, according to the most recent report from the country’s environmental regulator, Ibama. The origin of the leak remained unknown, according to Brazilian Vice-President Hamilton Mourao.

With pressure from the public and courts growing for Brazil’s government to do more, Mourao said Monday that 5,000 more troops will be dispatched to help with the cleanup.

“The most we can do today is have trained people to collect this oil that is reaching our beaches,” Mourao said, adding that investigations into the source of the contamination continued.

Watch as volunteers clean up the oil from Brazil’s beaches:

Oil has been washing up on the shores of northeastern Brazil for two months, but its origin has remained a mystery so far. 0:53

Oceanographers and environmental groups have been criticizing the government’s response as slow and ineffective, and many Brazilians are working to clean beaches themselves.

The government suffered similar criticism when fires destroyed large swaths of the Amazon region in June and July. It eventually sent soldiers to help local firefighters extinguish the blazes.

In the oil spill, 1,500 troops had already been deployed in various locations. Environmental groups said the number of servicemen is insufficient considering that contamination spreads over 2,000 kilometres of coastline.

Federal courts in Pernambuco and Alagoas states said the government had 24 hours to install protection barriers around sensitive natural areas and ecosystems, such as mangroves, rivers and sea turtle spawning areas.

Brazil’s vice-president said that 5,000 more troops will be dispatched to help with the cleanup. (Diego Nigro/Reuters)

Mourao said all necessary means were adopted for the crude’s collection, reiterating prior comments from the environment minister.

On Monday, Petrobras said it had collected 280 tonnes of oil and sand from the beaches.

Brazil’s government has said the oil spill is Venezuelan in origin, but has mostly stopped short of blaming the government of Nicolas Maduro for the incident. Venezuela has denied it is to blame.