International human rights groups are urging Sri Lanka’s new president to immediately order security forces to cease all unlawful use of force against protesters who have been demonstrating against the government for months over the country’s economic meltdown.

A day after President Ranil Wickremesinghe was sworn in, hundreds of armed troops raided a protest camp outside the president’s office in the early hours of Friday, attacking demonstrators with batons in a move that Human Rights Watch said “sends a dangerous message to the Sri Lankan people that the new government intends to act through brute force rather than the rule of law”.

Two journalists and two lawyers were also attacked by soldiers in the crackdown. Security forces arrested 11 people, including protesters and lawyers.

Meenakshi Ganguly, South Asia director at Human Rights Watch, said in a statement released early on Saturday: “Urgently-needed measures to address the economic needs of Sri Lankans demand a government that respects fundamental rights.

“Sri Lanka’s international partners should send the message loud and clear that they can’t support an administration that tramples on the rights of its people.”

Also condemning the attack, rights group Amnesty International said “it is shameful that the new government resorted to such violent tactics within hours of coming to power”.

Kyle Ward, the group’s deputy secretary general, said: “The protesters have a right to demonstrate peacefully. Excessive use of force, intimidation and unlawful arrests seem to be an endlessly repetitive pattern in which the Sri Lankan authorities respond to dissent and peaceful assembly.”

Mr Wickremesinghe, who previously served as prime minister six times, was sworn in as president a week after his predecessor Gotabaya Rajapaksa fled the country after protesters stormed his residence. Mr Rajapaksa later resigned while exiled in Singapore.

Sri Lankans have taken to the streets for months to demand their top leaders step down to take responsibility for the economic chaos that has left the nation’s 22 million people struggling with shortages of essentials, including medicine, fuel and food.

While the protesters have focused on the Rajapaksa political dynasty, Mr Wickremesinghe has also drawn their ire as a perceived Rajapaksa surrogate.

Armed troops and police arrived in trucks and buses on Friday to clear the main protest camp near the presidential palace in the capital Colombo, where demonstrators had gathered for more than 100 days. They removed tents and blocked roads leading to the site.

The troops moved in even though protesters had announced they would vacate the site on Friday voluntarily.

Sri Lanka’s opposition, the United Nations, and the US have denounced the government’s heavy-handed tactics.

Despite heightened security outside the president’s office, protesters have vowed to continue their efforts until Mr Wickremesinghe resigns.

He was voted president by politicians this week – apparently seen as a safe pair of hands to lead Sri Lanka out of the crisis, even though he, too, was a target of the demonstrations.

On Friday, he appointed as prime minister a Rajapaksa ally, Dinesh Gunawardena, who is 73 and from a prominent political family.

On Monday, when he was acting president, Wickremesinghe declared a state of emergency giving him the power to change or suspend laws and giving authorities broad power to search premises and detain people.

Overnight, just hours after he was sworn in, he issued a notice under the state of emergency calling on the armed forces to maintain law and order nationwide – clearing the way for the move against the protest camp.

The protesters accuse Mr Rajapaksa and his powerful family of siphoning money from government coffers and of hastening the country’s collapse by mismanaging the economy. The family has denied the corruption allegations, but the former president acknowledged that some of his policies contributed to Sri Lanka’s crisis.