For years the highest-ranking Haitian official at the United Nations, Latortue, 69, was expected to get to work rapidly with a council of seven eminent Haitians to give shape to his new government.
Latortue had been living in Florida for the last several years.
His return on Wednesday coincided with an announcement by the US-led multinational force of a drive to seize illegal arms.
The decision came after US marines said they had shot dead two more Haitians in capital Port-au-Prince.
"You have got to take the guns off the street, if you have the ability to do it, and we do, to protect yourself and to protect the government," General James Hill, the head of the US Southern Command, said.
Civil war threat
Meanwhile, supporters of exiled Haitian President Jean-Bertrand Aristide have vowed to fight a civil war and kill US soldiers until their leader is allowed to return.
Slum dwellers in the crowded shantytown of Belair said they feared their impoverished lives would worsen under anyone but Aristide and threatened to fight the "foreign occupation" of their country.
"If they don’t bring back Aristide, I am going to kill the Americans," said an angry young man who gave his name as Sanson.
"You have got to take the guns off the street, if you have the ability to do it, and we do, to protect yourself and to protect the government"
General James Hill, Head, US Southern Command
"If the Americans stay in this country, we will make civil war," said Jur Teuba, a woman who led crowds chanting "our blood is Aristide's blood."
A former slum priest, Aristide left Haiti on 29 February as rebels closed in on capital Port-au-Prince. Aristide later accused the US and France of "kidnapping and forcing him to leave."
Also during the day, a high-level delegation from South Africa meanwhile met Aristide in Bangui, the capital of the Central African Republic.
South Africa has been a strong supporter of Aristide and had said earlier that it was willing to grant him asylum. Aristide, however, has not made any formal requests so far.
South African Foreign Affairs Ministry spokesman Ronnie Mamoepa said earlier the meeting was being held in coordination with the Caribbean Community and the African Union.
While South Africa has demanded an international investigation into Aristide's ouster, the African Union has dubbed the toppling of Aristide as unconstitutional.