Guatemala City, Guatemala - The government of Guatemalan President Jimmy Morales has said it is withdrawing from a UN-backed anti-corruption commission and is giving the body's staff 24 hours to leave the country, in a move that drew criticism from human rights groups and constitutional lawyers.

Speaking to reporters on Monday, Morales accused the International Commission Against Impunity in Guatemala, commonly known as CICIG, of polarising the country and putting its security at risk, as well as violating human rights and being allied with criminal structures and "terrorists".

"The State of Guatemala terminates the agreement with CICIG because of the serious violation of national and international laws," Morales said in Guatemala City, adding that his government had waited 16 months for the UN to respond to their complaints.

"The CICIG has put at risk the sovereignty of the people of Guatemala," Morales said, accusing the UN of not "seeking solutions" to alleged violations.

Morales made the comments surrounded by the families of those he asserts are falsely accused by the CICIG, including a Russian family which was prosecuted and sentenced to seven years in prison for using a falsified Guatemalan passport.

Leading up to the press conference, Sandra Jovel, Guatemala's minister of foreign affairs, had informed UN chief Antonio Guterres of the unilateral decision.

"The agreement is finalised," Jovel told reporters. "We hope the secretary-general will respect of sovereignty."

Constitutional crisis

The CICIG was formed in 2006 upon the request of the Guatemalan government to combat high rates of impunity for crimes. It was ratified by the country's legislative branch in 2007 following a massive police scandal.

The commission's 2015 corruption investigation in the administration of Otto Perez Molina led to the resignation of the former president, who is currently facing criminal charges.

Morales utilised an anti-corruption platform in the country's 2015 election, promising voters he was "not corrupt, or a thief". Yet he and his family have faced corruption allegations since taking office in January 2016.

Allies of Morales in the country's Congress led by Estuardo Galdamez, of the FCN-Nacion party, had called on the president to unilaterally repeal the law that formed the body. Many congressional members are currently under investigation for corruption.

In August last year, Morales announced that he would not be renewing the mandate of the anti-impunity body. The president also attempted to declare CICIG head Ivan Velasquez a "persona non-grata" and bar him from the country.

But the country's Constitutional Court in September ruled against the ban on Velasquez, ordering that he must be permitted to re-enter Guatemala. The government has remained steadfast in its position, sparking a deepening constitutional crisis.

Earlier on Monday, Stephane Dujarric, UN spokesperson, had urged Guatemala's government to allow the free movement of CICIG staff in the country, as in accordance with the 2006 agreement.

His call came two days after Guatemalan immigration officials denied Yilen Osorio, a Colombian CICIG investigator, entry into the country and arrested him upon arrival.

The detention violated a December 21 court order issued by Guatemala's highest court which said the government must allow entry for 11 CICIG investigators whose visas were revoked earlier that month. The government argued that the investigators posed a threat to national security, giving them 72 hours to leave the country.

Osorio was finally permitted to enter the country after being held for some 24 hours following an order by the Constitutional Court.

'Against the law'

Oswaldo Samayoa, a Guatemalan constitutional lawyer, said that among those whose visas were removed are the lead investigators of the cases against Morales, his brother and son.

"There is clearly a conflict of interests in the decisions of Morales," Samayoa told Al Jazeera. "It is a form of revenge disguised in the discourse of sovereignty."

Commenting on Guatemala's CICIG withdrawal, Samayoa said Monday's announcement was "disastrous for our country, for our democracy and our fragile institutions".

"All these actions are against the law and constitution," Samayoa added.

"The agreement with the United Nations that formed the CICIG says that only the UN can end the anti-corruption body," explained Samayoa, pointing to articles 11 and 14 of the agreement and citing article 149 of Guatemala's constitution, which upholds the country's commitment to human rights and international accords.

Iduvina Hernandez, director of human rights organisation Security in Democracy, alleged that Morales "is destroying the institutional order".

"These actions are a coup d'etat against the rule of law," Hernandez told Al Jazeera. "This is being carried out by those in government that wish to maintain their privileges."

The president's move was also condemned by Democrats in the United States, including Representative Norma Torres.

"Jimmy Morales' presidency has set the country back years, if not decades," Torres said in a statement.

"Morales had a historic opportunity to give Guatemalans the transparent and effective government that they deserve. Instead, when faced with the prospect of criminal investigation by CICIG and the public ministry, he chose to destroy the rule of law in order to protect himself," Torres wrote.

"He has engaged in a pattern of behaviour that has undermined Guatemala’s justice system and brought the country to the brink of a constitutional crisis."