• The U.S. is sending FBI and DHS officials to Port-au-Prince as soon as possible, the White House said.
• The U.S. has no plans to send military assistance at this time, White House officials told NBC News.
• The State Department told CNBC that it was aware of the arrest of two U.S. citizens in Haiti and is "monitoring the situation closely."
• Gunmen assassinated Jovenel Moise and wounded his wife in their private residence Wednesday, plunging the Caribbean nation into political crisis.

The U.S. is sending senior FBI and DHS officials to Port-au-Prince as soon as possible to assist with the investigation into the assassination of Haitian President Jovenel Moise, the White House said Friday, in response to the Haitian government's formal request for assistance.

"The United States remains engaged and in close consultations with our Haitian and international partners to support the Haitian people in the aftermath of the assassination of the president," White House press secretary Jen Psaki said at a press briefing.

However, the U.S. has no plans to send military assistance at this time, White House officials told NBC News on Friday afternoon, amid reports that Haitian officials had requested troops to secure critical infrastructure.

An FBI spokesperson said the agency is working with the U.S. Embassy in Haiti and law enforcement partners to determine how to assist with the investigation.

Haiti's ambassador to the U.S., Bocchit Edmond, said on Friday that the Haitian government's request outlined the "critical role" the FBI and the Justice Department can play in the investigation into the assassination. 

Edmond added that the Haitian government also requested the U.S. impose sanctions on perpetrators involved in the attack under the Global Magnitsky Act, which authorizes the U.S. president to deny entry to and impose economic sanctions against any foreign individual responsible for extrajudicial killings or human rights abuses.

"We look forward to engaging with our US partners as we seek truth and justice," Edmond said in a series of posts on Twitter.

Colombia has also announced that it will be assisting with the probe, Reuters reported Friday. Colombian President Ivan Duque said the head of Colombia's national intelligence directorate and the intelligence director for the national police will be sent to Haiti with Interpol.

The U.S. State Department confirmed on Friday that two Americans have been arrested by Haitian authorities following the president's assassination.

"We are aware of the arrest of two U.S. citizens in Haiti and are monitoring the situation closely," a State Department spokesperson told CNBC. "We remain committed to cooperating with Haitian authorities on the investigation."

The State Department declined to comment any further, citing privacy considerations, and pointed to Haitian authorities for further information.

Haitian police on Friday identified the American suspects, who are of Haitian descent, as James Solages and Joseph Vincent. Solages, 35, is the youngest of the suspects, and Vincent, 55, is the oldest, according to a document shared by Mathias Pierre, Haiti's minister of elections.

They are among at least 20 suspects that Haitian police have detained so far in the shocking assassination, alongside 18 Colombians.

The search continues for at least five additional suspects, and four others were killed by police in an exchange of gunfire, according to Haitian police. Haiti Chief of Police Leon Charles on Thursday urged the Haitian public to help authorities locate the other suspects but not to "take justice into their own hands."

U.S. President Joe Biden on Wednesday condemned the assassination and said he was "shocked and saddened to hear" about it.

"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," Biden said in a statement. 

A group of gunmen assassinated Moise and wounded his wife in their private residence Wednesday, plunging the Caribbean nation into an even deeper political crisis that has been fueled by gang violence and protests against the late president's increasingly authoritarian rule. 

Claude Joseph, Haiti's interim prime minister, said the police and military were now in control of security in Haiti. Authorities declared a siege in the country following the killing and closed the international airport. 

Edmond has called for an international investigation into the assassination and has asked the U.S. for assistance in bolstering Haitian security. 

The State Department on Thursday vehemently denied that the Drug Enforcement Administration was involved in the assassination after the attackers reportedly identified themselves as DEA agents. 

Edmond has said the attackers were posing as DEA agents, describing them as "well-trained professional killers, commandos" based on a video shot from a neighbor's house during the attack. He also noted that some spoke Spanish. Haitians speak French and Creole. 

Protests against the late Haitian president turned violent in recent months as opposition leaders and their supporters demanded his resignation.

Moise had been accused of seeking to increase his power even after his term expired in February. Opposition leaders pointed to his approval of decrees limiting powers of a court that audits the government and his creation of an intelligence agency that answers only to him.

Opposition leaders and their supporters also rejected Moise's plans to hold a constitutional referendum with controversial proposals that would strengthen the presidency's power.

— The Associated Press contributed to this report.