The Canadian government, in an unprecedented move designed to quell Quebec's secessionist Front de Liberation du Quebec (FLQ), yesterday suspended civil liberties and arrested over 250 FLQ members and sympathizers.

Invoking the War Emergency Act-an authorization of martial law-the Canadian government sought to cripple the increasingly militant activities of the FLQ. Thirteen days ago, secessionists kidnapped British diplomat James Cross; seven days ago, Quebec Labor Minister Pierre Laporte was abducted.

Negotiations between the FLQ and the Trudeau government over release of the captives broke down early yesterday morning. FLQ representative Robert Lemieux, seeking the release of 23 separatists convicted or awaiting trial for terrorism, dismissed the final government offer to free five prisoners in exchange for Cross and Laporte as "an incredible mockery." One hour later, at 4 a. m., the government issued its proclamation suspending civil liberties and outlawing the FLQ. Lemieux was among those arrested yesterday.

Prime Minister Trudeau, a Quebecborn millionaire with a master's degree from Harvard, stated that the exact measures to be imposed would be announced at 11 a. m. today. While the War Emergency Act grants his government virtually unrestricted powers to suppress insurrection, indications are that the measures announced yesterday will be largely limited to search and seizure without warrant and regulation of public assembly.

Hundreds of troops and police took part in fencing off parts of Montreal yesterday, while additional hundreds made arrests of FLQ members and sympathizers.

Penalties of five years in prison have been set for those who "advocate, promote, or engage in the use of force or the commission of criminal offenses" in seeking governmental change.