Armed men attacked a convoy of cars carrying the US envoy to Bangladesh in the capital Dhaka on Saturday night, US officials said.
Ambassador Marcia Bernicat and her security team were able to get away unharmed, but two cars were damaged.
It comes as thousands of students and school children continue a week-long protest calling for safer roads.
Police used tear gas to disperse crowds on Sunday. At least 50 protesters have also been injured in street attacks.
Local media reported that political activists belonging to the governing party beat students marching towards their offices.
The students were demanding to know why protesters were attacked on Saturday, in clashes which left dozens injured.
The US ambassador condemned the violence.
“Nothing can justify the brutal attacks and violence over the weekend against the thousands of young people who have been peacefully exercising their democratic rights,” a statement on the embassy’s Facebook page said.
“The peaceful demonstrations of the past week in favour of better vehicle and road safety, led by students and school children across Bangladesh, have united and captured the imagination of the whole country.”
Meanwhile, a prominent photojournalist and human rights activist, Shahidul Alam, was detained by police on Sunday over Facebook posts relating to the protests.
Mr Alam had criticised the government’s handling of the protests in interviews with international media. (Courtesy BBC)