The U.S. embassy in the Haitian capital of Port-au-Prince told American citizens to remain inside until further notice Sunday as the city continues to be gripped by violent protests.

"Do not travel to the airport unless you confirmed your flight is departing,” the State Department cautioned. "Flights are canceled today [Sunday] and the airport has limited food and water available.

"Telecommunication services, including internet and phone lines, have been affected throughout Haiti. It may be difficult to reach people through normal communication methods."

The State Department also expressed its "deepest condolences" to all those affected by the ongoing violence.

“We are closely monitoring the situation and remain in close contact with Haitian authorities to verify the welfare and whereabouts of U.S. citizens in the area,” added the travel advisory.

At least three people have been killed, including two protesters who were fatally shot by authorities and a security guard who was beaten to death by demonstrators after attempting to disperse a crowd by firing his gun into the air.

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An estimated 120 Americans are believed to be staying at a Port-au-Prince hotel targeted by protesters, who attempted to bypass security and set the building ablaze. Youth groups and missionaries from an array of U.S churches are also stranded in the Caribbean nation, unable to make it safely to the airport for departure.

The Haitian government on Saturday halted a planned fuel price hike after tension and fighting escalated late last week. Haiti Prime Minister Jack Guy Lafontant had previously declared that fuel prices needed to be raised to balance the budget and announced a 38 percent increase for gasoline, diesel and kerosene. Despite the Lafontant government's concession to public pressure, the anger and remains.

A source on the ground in Haiti described the situation as "on fire" and only getting worse, with more major demonstrations expected Sunday in the wealthy enclave of Pétion-Ville, south-east of the capital city.

"Government vehicles are moving to high ground, we have been told to initiate total lockdown measures immediately,” the source added. “We have to see what develops.”