KUALA LUMPUR, Malaysia — Police officers arrested almost 1,700 people and fired tear gas at protesters here in Malaysia’s capital on Saturday in an attempt to prevent an afternoon rally by advocates of an overhaul of elections.

Officials said that protest leaders were among those arrested.

Demonstrators were seen scattering as the police fired tear gas on Saturday afternoon. In one late-afternoon skirmish, the police volleyed tear gas at thousands of protesters near the city’s Central Market. The Associated Press reported that the police also used chemical-laced water to disperse some demonstrators.

Roads leading into Kuala Lumpur, as well as some streets in the city, remained closed late in the afternoon as helicopters hovered over the city center.

The confrontation was the culmination of weeks of tension, as activists have called on Prime Minister Najib Razak to change the way elections are conducted. The next vote must be held by mid-2013, but there is speculation it could be called as early as this year.