German-born American architect Helmut Jahn, known for his postmodern steel-and-glass structures, has died aged 81 in Illinois after being hit by two vehicles while he was riding his bicycle, police said Sunday.

Jahn died on Saturday afternoon in Campton Hills, about 60 miles (100 kilometers) west of Chicago, when he "failed to stop at a posted stop sign" at an intersection, according to police.

The two vehicles were traveling in opposite directions, police said, adding that Jahn died at the scene and one driver was taken to hospital with minor injuries.

After graduating in Munich in 1965, Jahn moved to Chicago to study at the Illinois Institute of Technology, a school associated with influential Modernist architect Ludwig Mies van der Rohe.

Jahn made his name in the 1970s and 1980s with buildings in Chicago including the controversial Thompson Center and the United Airlines Terminal at O'Hare International Airport.

Helmut Jahn arrives at the White House in 2011 to attend a state dinner hosted by President Barack Obama for German Chancellor Angela Merkel
Helmut Jahn arrives at the White House in 2011 to attend a state dinner hosted by President Barack Obama for German Chancellor Angela Merkel GETTY IMAGES NORTH AMERICA / BRENDAN SMIALOWSKI

He was also involved in the design of the FBI headquarters in Washington and later built the Munich Airport Center and the Sony Center in Berlin.

"Jahn was one of the most inventive Chicago architects whose impact on the city... will never be forgotten," said Chicago mayor Lori Lightfoot on Twitter.

"His architectural footprint will be felt & seen across the globe for generations to come."

Blair Kamin, former architecture critic of the Chicago Tribune, told the paper on Sunday that Jahn was a "dashing star of an architect."

"His architecture was always exceptional. And, as time went on, he was regarded as less of a 'Flash Gordon' character and more of a modernist master."