“We repeat our calls for the military to relinquish power, restore democratically elected government (and) release those detained,” State Department spokesman Ned Price told reporters.
In Mandalay, the country’s cultural capital and seat of Myanmar’s pre-colonial monarchy, witnesses saw security forces fire tear gas directly at protesters waving the red flags of Suu Kyi’s National League for Democracy (NLD) party.
State media claimed that the crowd had used “obscene language” and thrown objects at police, injuring four officers, in its first direct mention of the street protests since they began on the weekend.
“Therefore, the police members dispersed in accordance with the methods and laws,” the state-run Global New Light of Myanmar newspaper reported, without mentioning other police confrontations elsewhere in the country.
Hundreds of protesters had returned to the streets of Yangon on Wednesday morning, where the day before a large crowd faced off against water cannon and a phalanx of riot police near Suu Kyi’s residence.
Though there were no reported clashes with authorities in the commercial hub on Tuesday, university student Khin Nyein Wai said she was still afraid.
“I still came out as I do not like the military dictatorship,” she told AFP. “This is for our future.”
‘Respect the vote’
The military justified last week’s power grab by claiming widespread voter fraud in the November polls, which saw a landslide for Suu Kyi and her party, and quickly moved to stack courts and political offices with loyalists.
In the 10 days since army chief Min Aung Hlaing ousted the Nobel laureate from power and ended a decade of civilian rule, Myanmar has been roiled by a burgeoning civil disobedience campaign and massive street protests.
Medical staff, air traffic controllers and teachers have staged strikes, fronted for work while wearing red ribbons on their uniforms or posed for photos while brandishing the three-finger salute adopted by the anti-coup movement.
Protesters on the streets have called for the release of Suu Kyi -- who has not been publicly seen since she and other top political leaders were detained -- and for the generals to respect the results of the last election.
Demonstrations have raged across the country from the Chinese border town of Muse to the southern city of Dawei.
By Tuesday a ban on gatherings and a nightime curfew was in effect in the three biggest cities of Yangon, Mandalay and Naypyidaw, along with various other towns.
The United Nations voiced “strong concern” over Tuesday’s violence.
“The use of disproportionate force against demonstrators is unacceptable,” said Ola Almgren, the UN resident coordinator in Myanmar.
European Union foreign policy chief Josep Borrell warned the bloc could impose fresh sanctions on Myanmar’s military, but said any measures should be targeted to avoid hitting the wider population.
“We are currently reviewing all our options,” he told the European Parliament on Tuesday.
New Zealand became the first country taking action to isolate the junta on the same day when it announced the suspension of high-level military and political contacts with Myanmar.
The UN Human Rights Council said it would hold a special session on Friday to discuss the crisis.