BRUSSELS — The Belgian government has lost its majority in Parliament after its biggest coalition partner, the right-wing Flemish party, left in opposition to the planned signing this month of an international agreement on migration.

Prime Minister Charles Michel, in announcing the end of his majority government during a news conference on Saturday, said, “One party, the N-VA, calls into question our common decision to join the U.N. migration pact, taken earlier this year in July.”

Mr. Michel said he would try to lead the remaining minority government to “ensure stability.”

On Sunday, he formalized the resignation of the five N-VA ministers from his government, appointing ministers from the remaining coalition partners in their place.

The political moves came amid demonstrations by about 1,000 people in Brussels, inspired by the “Yellow Vests” protests in neighboring France. While the world’s eyes are on France, similarly violent demonstrations have occurred in Brussels in the past two weekends, led by people who, analysts say, are angry with recent increases in fuel taxes and say that everyday life has become unaffordable.