SAN’A, Yemen—The minority group whose militants have overrun Yemen’s capital said it would take power by force and impose its own political order if a consensual arrangement to end a political standoff isn’t reached by Wednesday.

The Houthis—who desire a greater role in the government—met with other Yemeni factions and a United Nations envoy, Moroccan Jamal Benomar, in the aftermath of President Abed Rabbo Mansour Hadi’s abrupt resignation on Jan. 22.

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