PORT-AU-PRINCE, Haiti—Haitian President Jovenel Moïse was assassinated in an attack on his private residence, according to a statement Wednesday from the country’s interim prime minister, who called the killing a “hateful, inhumane, and barbaric act.” First Lady Martine Moïse was shot in the overnight attack and hospitalized, interim Premier Claude Joseph said. Haiti was already in a precarious political situation before the assassination, having grown increasingly unstable and disgruntled under Moïse. The president ruled by decree for more than two years after the country failed to hold elections and the opposition demanded he step down in recent months. “The country’s security situation is under the control of the National Police of Haiti and the Armed Forces of Haiti,” Joseph said in a statement from his office. “Democracy and the republic will win.” In the early morning hours of Wednesday, the streets were largely empty in the Caribbean nation’s capital of …