"The US actively directly engages with the highest levels of Bangladesh government, (along) with exporters, and buyers on the issues of workers' rights and safe working conditions," State Department spokesperson Patrick Ventrell said.
The businesses operating in the ill-feted building near Dhaka appear to have links to numerous companies in the US and Europe, Ventrell said in his daily news conference.
"We continue to speak with many US companies that source from Bangladesh about workplace safety and the role that buyers can play in improving working conditions," he said.
"We will continue to engage with US companies to discuss what role they can play in improving working conditions, including in Bangladesh," Ventrell said.
The eight-storey Rana Plaza near capital Dhaka, which housed five garment factories, a branch of Brac Bank and a shopping complex, had collapsed on April 24.