Police in Malaysia say they have released some 500 people arrested during a demonstration for election reforms.

Officials say they would decided later whether to press charges on any of them.

Tens of thousands of protesters gathered Saturday in Kuala Lumpur's Independence Square, despite a ban on holding the rally there.

The activists say the country's Election Commission is biased and that Prime Minister Najib Razak's ruling coalition, which has held power for more than 50 years, will have an unfair advantage in elections that could be called as early as June.