KUALA LUMPUR, Malaysia — Malaysia’s leader sought to curb rifts between the Malay majority and ethnic minorities Thursday, saying the country could end up in tatters like Bosnia or Rwanda if races quarrel over economic rights.

In a speech broadcast nationwide, Prime Minister Najib Razak tried to please his main Malay constituency with assurances that an affirmative action program would continue to assist them. But he also acknowledged contributions made by the ethnic Chinese and Indian minorities, mindful that their votes would be precious in the next elections, expected to be held before they are due in 2013.

“Today, Malaysians are confronted with ceaseless assaults on the main foundations of race relations,” Najib said in a speech at the annual national convention of his United Malays National Organization party, the core of the ruling National Front coalition.

Malaysia has enjoyed decades of amicable race relations, but unease has risen in recent years amid complaints by minorities that they endure discrimination because of the affirmative action program that benefit Malays in business, jobs and education.

The Malay privileges stem from a “national social contract,” drawn up by various races at the time of independence in 1957, which put the majority community on a higher footing in exchange for sharing political power with minorities and giving them citizenship.

Najib said Malays made a “huge sacrifice” by agreeing to share the country with minorities, most of whom are descended from immigrants who sought work here during British colonial rule in the 19th and early 20th centuries. Malays make up 60 percent of the population, while Chinese account for 25 percent and Indians 8 percent.

Malaysians should stop arguing about Malay and minority rights, Najib said, adding that history showed how grudges between communities triggered the Holocaust, the Palestinian conflict in the Middle East and killings in Bosnia and Rwanda.

“So imagine what the result will be if generations of Malaysians take a stand to question the national social contract that has been drawn up by their predecessors,” Najib told more than 2,000 top party officials.

He nevertheless urged Malays not to be “obsessed” about their rights, saying they should wisely use opportunities given to them and also bolster their capability to compete globally.

He noted non-Malays still control much of Malaysia’s wealth despite nearly four decades of affirmative action policies, which followed 1969 riots that killed at least 200 people amid frustration among Malays over Chinese economic dominance.

Dissatisfaction about affirmative action — including among some Malays who say it makes the country less competitive and benefits mainly the well-connected elite — prompted many to vote for a three-party opposition alliance in 2008 general elections.

Najib’s coalition now has slightly less than a two-thirds majority in Parliament, one of its weakest in 53 years of rule. The opposition hopes to win the next elections, promising to ensure true justice for all races.