KUALA LUMPUR - Cracking down on the opposition, the Malaysian police arrested a top politician on Wednesday, briefly detained the editor of the leading anti-government newspaper and charged another prominent leader with spreading racial discord.

Opposition leaders said the arrests could mark the start of a campaign to stifle criticism of Prime Minister Mahathir bin Mohamad's government following bitterly contested elections.

''This is not the way to heal the nation after the elections,'' said Lim Kit Siang, national chairman of the Democratic Action Party. ''It only deepens the wounds and has far-reaching repercussions for nation-building in years to come.''

Karpal Singh, the party's deputy leader, was taken to a Kuala Lumpur police station, Mr. Lim said. The police did not immediately confirm the arrest of Mr. Karpal, a prominent lawyer who represents the jailed former deputy prime minister, Anwar Ibrahim, in his sodomy trial.

Mr. Karpal was charged with sedition for a statement made in court during the trial, Mr. Lim said. Mr. Karpal surrendered after a warrant was issued.

The police also charged Zulkifli Sulong, editor of Harakah, the newspaper of the opposition Pan-Malaysian Islamic Party, with sedition.

''If I'm found guilty, the newspaper could be suspended,'' Mr. Zulkifli said shortly after his arrest.

Mr. Zulkifli said he was told to appear in a Malaysian Sessions Court on Thursday to answer charges regarding an article on Mr. Anwar's trial published in August. Mr. Zulkifli was detained, then freed on bail. If convicted, he faces six months in prison and a fine of 5,000 ringgits ($1,320)

In the third aspect of the crackdown, the police charged the leader of the National Justice Party, Marina Yusoff, with ''provoking racial discord.'' She, too, could face a jail term if convicted.

The Justice Party vice president, Tian Chua, said: ''It looks like the persecution is on. I think they will go for a new round of attacks on the opposition. I am not optimistic.''

Opposition parties made significant strides in the November general elections, when they took two states and nearly tripled their seats in Parliament.

Although Mr. Mahathir's party maintained its overwhelming dominance in Parliament, it was seriously undermined by opposition gains among its grassroots ethnic Malay supporters.

Harakah, published twice weekly, has come under fire recently from government officials saying it is ''full of lies and slander.''

In the past week, international media freedom groups have pressed the government not to ban the newspaper, following threats by Deputy Prime Minister Abdullah Ahmad Badawi that Harakah's publication permit might be rescinded.

Mr. Karpal, a former member of Parliament, is one of the most vocal critics of the 74-year-old prime minister, who has governed Malaysia for 18 years. He has routinely accused Mr. Mahathir's allies of fabricating the charges against his client.

Mr. Anwar, 52, is serving a six-year sentence for corruption. He was dismissed by Mr. Mahathir in September 1998. He says the charges against him were trumped up by political enemies.

The arrests came on the day Mr. Mahathir left for a two-week vacation in Argentina and the Caribbean, leaving Abdullah Ahmad, who is also interior minister, to run the government.