KUALA LUMPUR, Sept 16 — City police have said they will launch an immediate investigation into the Opposition-backed rally held today after reiterating that the event was unlawful.

Kuala Lumpur Police Chief Datuk Allaudeen Abdul Majid said at a press conference held at the Dang Wangi district police headquarters here that investigators will summon "anyone” who was necessary to assist in the probe, as he cited several potential violations of the Peaceful Assembly Act by the rally’s organisers.

"We will look into everything and we will act accordingly,” he told reporters.

About a thousand people had earlier gathered at the Masjid Jamek in Kampung Baru here before marching towards Jalan Tunku Abdul Rahman in a rally to protest what they alleged to be political tampering in the corruption trial of Deputy Prime Minister Datuk Seri Ahmad Zahid Hamidi by Prime Minister Datuk Seri Anwar Ibrahim’s government.

Protesters, believed to be mostly supporters of Perikatan Nasional, demanded that the police investigate Attorney General Datuk Ahmad Terrirudin Mohd Salleh, among others.

Two days ago, Bukit Aman Criminal Investigation Department director Datuk Seri Mohd Shuhaily Mohd Zain said the organisers failed to provide all the necessary information when submitting the legally required notice, such as their names and the location of rally.

Shuhaily said the police were forced to "reject” the notice because of the omissions, but lawyers have questioned if the agency has the authority to do so as the PAA states that the authorities only need to be "notified”.

Allaudeen said today Section 10 of the PAA compels the organisers to provide those details in accordance with the format outlined by the Act, as the information is crucial to help the police facilitate the protest, including gathering feedback from residents or businesses where the protest would be held.

"They need to provide this information according to the format of the form. It’s not enough to just write a letter in,” he said.