Malaysian authorities detained three anti-government figures, charged a student activist with sedition and seized hundreds of opposition newspapers Thursday, raising political tensions after recent national elections triggered claims of fraud.

Opposition activists have staged numerous peaceful demonstrations since the May 5 general elections, which the National Front coalition won with a weakened parliamentary majority. The activists insist the coalition, which has governed since 1957, retained power through bogus ballots and other irregularities, though Prime Minister Najib Razak and electoral authorities deny manipulating the results.

The latest arrests involve Tian Chua, a senior official in opposition leader Anwar Ibrahim's People's Justice Party; Haris Ibrahim, a rights activist who leads an anti-government group; and Tamrin Ghafar, an opposition party member. The men had criticized the National Front at a recent political gathering.

The three were arrested separately and taken to a police station where lawyers were informed they were under investigation for sedition and would be held overnight.

The Prime Minister's office issued a statement saying the men were detained "after the police received numerous reports against the defendants by members of the public."

"In such circumstances the police are required to investigate and are following due and proper process," the statement said, adding that the men would face "fair and open court proceedings" if charged.

After his arrest, Chua tweeted that Malaysians should not allow themselves to be "overtaken by fear (but should) continue to assemble peacefully and have faith."

Their arrests occurred hours after prosecutors charged student Adam Adli, 24, with making seditious statements that included calling for people to "go down to the streets to seize back our power" while addressing a political forum. He pleaded innocent at a Kuala Lumpur district court Thursday and was released on bail ahead of a hearing July 2.

Sedition as defined by Malaysian law includes promoting hatred against the government.

Rights activists have long criticized Malaysia's anti-sedition law as a tool to curb democratic dissent. Najib said last year the government planned to eventually abolish the Sedition Act, which was introduced in 1949 during British colonial rule, and replace it with new laws that would strike a better balance between allowing freedom of speech and ensuring public stability.

Adam, who was arrested last weekend, faces three years in prison and a fine if convicted.

Hundreds of people demonstrated peacefully in recent days against Adam's arrest. Adam became publicly known in 2011 when he brought down a flag bearing Najib's portrait at the ruling party's headquarters during a demonstration. He was subsequently suspended for three semesters from his teaching course at a Malaysian state-backed university.

Separately Thursday, the Home Ministry said it had seized more than 2,500 copies of newspapers published by opposition parties from stores nationwide since Wednesday. The government-issued publication licenses for those newspapers specifies they should be distributed among party members only and were not for retail sales, the ministry said in a statement.