Bolivia's president has cancelled an emergency meeting to discuss energy reform after Congress and judiciary representatives refused to attend.
The meeting's cancellation is a serious blow to Mr Mesa
Carlos Mesa says he will not sign a Congress-inspired law which would increase taxes on foreign oil and gas companies by a third.
Bolivian business organisations say the law will damage the economy.
The BBC's Elliott Gotkine says the cancellation of the meeting is a serious blow to Mr Mesa.
He says it adds to the sense of uncertainty in Bolivia.
As it stands, the bill would increase the total taxes and royalties paid by foreign energy firms to 50% of their revenues.
Mr Mesa is expected to send a watered-down version back to Congress. He has until Tuesday to make clear his formal position.
Powerful indigenous groups are pressing for nationalisation of the energy industry.
Our correspondent says more demonstrations are expected next week.
A crisis over the energy industry brought down Mr Mesa's predecessor, Gonzalo Sanchez de Lozada.
As the meeting was cancelled, an explosive device went off outside an office belonging to the Brazilian oil company, Petrobras. There were no injuries.