Western officials are criticizing Myanmar authorities after police there beat student protesters with batons to break up a march demanding that the government scrap an education reform law.
The officers turned on the students Tuesday in Letpadan after they tried to push through a police barricade. Witnesses say police chased down the protesters, kicking and beating them before throwing them into wagons.
More than 120 people were arrested and many were injured in the clashes, which sparked fresh worries that recent democratic reforms were being reversed in Myanmar, which is also known as Burma.
At a regular briefing in Washington, U.S. State Department spokeswoman Jen Psaki condemned the use of force against the students.
"We urge the government of Burma to respect the right of protesters to assemble peacefully as a means of expressing their views," Psaki said Tuesday. "Freedom of assembly is an important component of any democratic society."
The European Union called for a formal investigation, adding that it was "deeply concerned" at the incident.
Human Rights Watch also urged Myanmar to end its crackdown on student protests and "investigate officers responsible for the use of excessive force against protesters."
"The savage beating of students by police and plainclothes thugs marks an ugly return to the street violence of military rule," said Brad Adams, Asia director at Human Rights Watch. "The government needs to rein in abusive police, disband unaccountable auxiliaries, and permit peaceful demonstrations."
The group, made up of hundreds of students, set off last month from Mandalay, trying to reach Yangon, Myanmar's main city. But the march was stopped by police on March 2 in the city of Letpadan, about 130 kilometers north of Yangon.
The students say the government's education reform law will centralize control of universities in Myanmar. They also want more government spending on education as well as the freedom to organize teachers and students.
Myanmar has been run by a semi-civilian government since 2011, after decades of military rule. But pro-democracy activists say they believe they are seeing a return to the old Burma, where military rulers banned free speech and violently cracked down on protests.