Security forces in Haiti killed at least three people, repelling an attack on the central bank as gang violence surges in the capital of Port-au-Prince, an employee said Tuesday.

The Bank of the Republic of Haiti (BRH) is one of the few key institutions still operating in the business district of the capital, which has been overrun by armed groups for the past three weeks.

On Monday, a "group of criminals" attacked its building but were driven back by the bank's security guards as well as police and armed forces, a bank employee told AFP.

The employee, who requested anonymity, said three or four suspected criminals had been killed, adding that a bank security guard was also shot and wounded.

Writing on X, previously Twitter, the bank said Tuesday: "Following an incident yesterday near the site of the BRH on Rue Pavee, security forces and the bank's security team acted with professionalism and efficiency."

The bank also wrote it was "deeply grateful" to its security guards and the police for "their vigilance and constant commitment to protecting our community."

Haiti has been rocked by surge in gang violence since late February when armed groups raided a prison, releasing thousands of inmates, as they demanded Prime Minister Ariel Henry resign.

Last week Henry agreed to step aside to allow the formation of an interim government, following pressure from neighboring Caribbean countries and the United States.

Talks among political parties and others are underway to form a transitional council that would name an interim prime minister to get the country ready for elections at some point. Haiti now has no president or parliament. Its last election was in 2016.

No official timeline for forming this council has been announced, but United Nations Secretary-General Antonio Guterres on Tuesday urged "all Haitian stakeholders to put aside their differences and take immediate action on the implementation of the transitional governance arrangements," his deputy spokesman Farhan Haq told reporters.

The United States on Tuesday reiterated its optimism at an update on the process to form the transitional council, saying that Guyana, the chair of the regional CARICOM body, is in charge of the process.

"We believe (the council) is vital to paving the way to not just free and fair elections, but the deployment of the MSS as well," State Department spokesman Vedant Patel told reporters, referring to an anticipated Kenyan-led Multinational Security Support Mission, envisioned to back up Haiti's overwhelmed police force. Kenya has put the mission on hold until a government is formed in Haiti.

The violence has exacerbated an already grim humanitarian situation, with the UN warning over the weekend of "famine and malnutrition" and "the near-collapse of basic services."

But the UN said Tuesday it was continuing to deliver assistance, despite the "tense and volatile" environment.

Still, the UN's response plan has "nowhere near enough (money) to respond to the scale of the needs on the ground, and we urgently need more support," Haq said.

Several areas in the Port-au-Prince metropolitan area were left without power, the public electricity utility said in a statement Monday, after at least four substations were "destroyed and rendered totally dysfunctional."

"Electricite d'Haiti has not been spared from the (recent) acts of vandalism and the terror of the bandits," the utility said.

On Sunday, a curfew was extended until Wednesday in the Ouest department, which includes Port-au-Prince. A state of emergency is set to end April 3.

The US and European Union member states are among the countries which have evacuated diplomatic personnel from Haiti due to the crisis.