Malaysian Prime Minister Najib Razak faces mounting calls for his resignation. Photo: Reuters/Kimimasa Mayama

Malaysian police raided the offices of pro-democracy group Bersih on Friday, a day before a demonstration organized by the group calling for Prime Minister Najib Razak to step down, the group said.

Thousands are expected to march in the Malaysian capital on Saturday to demand Najib resign over his involvement in a multibillion dollar scandal at state fund 1Malaysia Development Berhad (1MDB).

On its official Twitter account, Bersih said police and officials from the Companies Commission had taken part. Police had asked for some of the group’s assets to be seized, it said.

The police were still in the offices and there was no confirmation of any arrests made.

A police spokeswoman did not respond to requests for comment.

Bersih secretariat member Mandeep Singh said on Twitter the raid was conducted in relation to a probe under the penal code which covers “any activity detrimental to parliamentary democracy.”

Melissa Sasidaran, a lawyer for Bersih, tweeted that she and other lawyers had been prevented by police from entering the group’s office.

Bersih’s spokesperson and its chairwoman, Maria Chin Abdullah, were not immediately available for comment.

Last year, more than 200,000 attended a similar rally organized by Bersih, which has held several mass protests calling for electoral and institutional reforms since 2007.

Bersih, along with several other groups, is being investigated after reports that it received funds from Open Society Foundations (OSF), an organization linked to business tycoon George Soros.

Earlier this month, pro-government demonstrators protested outside the office of popular news portal Malaysiakini after the media group said it had received funds from OSF.

Najib’s administration has cracked down on the media and civil society in an attempt to silence criticism over his involvement in a money-laundering scandal at 1MDB.

Founded by Najib, who chaired its advisory board, 1MDB is currently the subject of investigations in at least six countries, including Switzerland, Singapore and the United States.

Najib has denied any wrongdoing.