Jakarta. Political activist Eggi Sudjana has been declared a treason suspect, a police spokesman said on Thursday.

Investigators interrogated Eggi for several hours as a witness in April after a member of the public filed a police report against him over a statement he allegedly made on April 17, encouraging supporters of presidential candidate Prabowo Subianto and his running mate Sandiaga Uno to embark on "people power" to overturn the result of last month's presidential election.

Eggi allegedly made the statement while addressing a crowd outside Prabowo's residence in South Jakarta. He stated that if the election result was not in favor of Prabowo-Sandiaga, it would be an indication of fraud.

"[Therefore,] as our guru, Mr. Amien Rais, has said, we must embark on people power. Do you agree? Are you brave [to do it]? When people power is implemented, we don't need to follow [legal] steps, because it will be the people's sovereignty," Eggi allegedly said at the time.

"This is maybe the way of Allah for Mr. Prabowo to be inaugurated [as president]. We don't need to wait until Oct. 20," he added, amid chants of "Allahu akbar!" ("God is greatest") from the crowd.

While addressing the crowd, Eggi introduced himself as an advisor to the so-called 212 alumni, in reference to participants in a rally by hardline Muslims on Dec. 2, 2016, which led to the defeat in the 2017 Jakarta gubernatorial election of the then-incumbent, Basuki "Ahok" Tjahaja Purnama, an ethnic Chinese Christian.

Police investigators decided to name Eggi a suspect after examining all evidence in the case and considering expert opinions, Chief Comr. Argo Yuwono told Metro TV on Thursday.

"Eggi Sudjana's legal status was upgraded to a suspect and he was called for further questioning on Monday next week," Argo said.

Eggi faces multiple charges, including under articles 107 and 110 of the Criminal Code on treason, which carry a maximum penalty of 20 years' imprisonment.

He accused law enforcers of unfair treatment while participating in the television talk show Mata Nadjwa, following his initial questioning.

On Thursday, Eggi attended a rally in Central Jakarta to urge the Election Supervisory Agency (Bawaslu) and General Elections Commission (KPU) to disqualify candidate pair Joko "Jokowi" Widodo and Ma'ruf Amin from the presidential election.

Eggi is one of the initiators of the rally, along with Kivlan Zein, who was also reported for treason in a separate case.

Coordinating Political, Legal and Security Affairs Minister Wiranto reiterated on Thursday that law enforcers would act firmly against anyone working against the national interest.

"The public must understand that we will take strong action, without discrimination, against any rally that is clearly violating the law," Wiranto said in Jakarta.

He said there was no political, but legal nuance in the decision, which aims to ensure the security of the state and public order.

Indonesia held its first simultaneous presidential and legislative elections on April 17, with the KPU scheduled to announce the official result on May 22.

However, Prabowo has declared victory at least three times, claiming to have won 62 percent of the vote, based on his camp's internal count, which has yet to be made public.

The Jokowi-Ma'ruf camp meanwhile expressed confidence on Wednesday that their nominee had won the presidential election after an internal count showed the pair having received more than 80 million votes, or more than 50 percent of the total.

The KPU had tabulated nearly 75 percent of the ballots by Thursday evening, with 56.21 percent of the vote in favor of Jokowi-Amin and 43.79 percent in favor of Prabowo-Sandiaga.