BERLIN - The assassination of Haitian President Jovenel Moise has drawn shock and condemnation from leaders in other parts of the world, along with calls for calm and unity in Haiti.

Moise was killed in an attack on his private residence early Wednesday, according to Haiti's interim prime minister. First lady Martine Moise was shot in the attack and is hospitalized. It wasn't immediately clear who was behind the assassination in the troubled Caribbean nation, which has grown increasingly unstable in recent years.

“We are shocked and saddened to hear of the horrific assassination of President Jovenel Moise and the attack on first lady Martine Moise of Haiti. We condemn this heinous act,” U.S. President Joe Biden said in a statement. “The United States offers condolences to the people of Haiti, and we stand ready to assist as we continue to work for a safe and secure Haiti.”

U.N. Secretary-General Antonio Guterres condemned the assassination “in the strongest terms” and stressed that “the perpetrators of this crime must be brought to justice,” U.N. spokesman Stephane Dujarric said.

“The secretary-general calls on all Haitians to preserve the constitutional order, remain united in the face of this abhorrent act and reject all violence,” Dujarric said. “The United Nations will continue to stand with the government and the people of Haiti.”

Colombian President Ivan Duque described the assassination as a “cowardly act” and also expressed solidarity with Haiti. He called for an urgent mission by the Organization of American States “to protect democratic order.”

Marlene Bastien, the executive director of Family Action Network Movement, a group that assists residents in Miami's Little Haiti community, said the “next few days are going to be very chaotic and contentious” as government supporters and opponents jostle for power.

“There is definitely a constitutional crisis and political void right now,” said Bastien.

“People are scared about tomorrow,” she said.

Bastian called on the Biden administration to take an active role in efforts to hold free, fair and credible elections in Haiti, following the assassination of Moise who had been ruling by decree.

“Here is a chance to do it right from the start,” said Bastien. “No more Band-aids. The Haitian people have been crying and suffering for too long.”

In Boston, which has one of the largest Haitian communities in the U.S., a pastor who heads a Haitian advocacy group, Dieufort Fleurissaint, said he's worried about reprisals and further unrest.

Fleurissaint said he's been checking in with family, friends and fellow pastors in Haiti since the early hours to make sure everyone stays at home for now.

“To kill and assassinate a president in his home just shows the level of insecurity in the country and how no one is exempt from the violence,” said the 59-year-old Fleurissaint, who has lived in the U.S. since he was 18. “It's unacceptable.”

He said his regular Wednesday morning prayer call with pastors in Haiti and the U.S. was inevitably focused on the killing.

“They're afraid for their lives,” Fleurissaint said. “The situation is dire. We're praying for peace in Haiti.”

Leaders across the world voiced fears that the assassination could lead to more unrest.

The European Union's foreign policy chief, Josep Borrell, warned in a tweet that “this crime carries a risk of instability and (a) spiral of violence.”

British Prime Minister Boris Johnson tweeted: “This is an abhorrent act and I call for calm at this time.”

Spanish Prime Minister Pedro Sanchez condemned the assassination.

“I'd like to make an appeal for political unity to get out of this terrible trauma that the country is going through,” Sanchez said during a visit to Latvia.

France's Foreign Affairs Minister Jean-Yves Le Drian said he was stunned by “this despicable assassination” and urged those involved in Haiti's political life to “show calm and restraint.”

In written statement, Le Drian advised French citizens in Haiti to exercise the utmost caution.

Taiwanese President Tsai Ing-wen offered her condolences via Twitter.

“We wish the first lady a prompt recovery, & stand together with our ally Haiti in this difficult time,” Tsai wrote. Haiti is one of only a handful of countries that maintains formal diplomatic relations with Taiwan, which China claims as its own.