Construction has been halted on the Obama Presidential Center in Chicago after a noose was found at the site.

Lakeside Alliance, a group of Black-owned construction companies behind the project, said they reported the incident to police on Thursday.

They are offering a $100,000 (£85,000) reward to find the perpetrators.

In a statement, the Obama Foundation - the former president's non-profit organisation - called the incident a "shameless act of cowardice and hate".

"Our priority is protecting the health and safety of our workforce," the statement said.

Governor of Illinois JB Pritzker has also condemned the incident, writing on Twitter that "the noose is more than a symbol of racism."

"It is a heart-stopping reminder of the violence and terror inflicted on black Americans for centuries," Mr Pritzker said.

The firm behind the project said it was halting construction to provide anti-bias training to staff and workers.

"We have zero tolerance for any form of bias or hate on our worksite," Lakeside Alliance said in a statement.

The looped rope is synonymous with the extrajudicial hangings or lynching of mainly black people in the United States in the late 19th and early 20th Centuries.

Work on the Center began in 2021, with Barack Obama and his wife Michelle attending a ground-breaking event last September.

The $500m (£424.3m) Center is due to open in 2025, and is expected to attract about 750,000 visitors a year.

On its website, the Obama Foundation said the Center "represents a historic opportunity to build a world-class museum and public gathering space that celebrates our nation's first African American President and First Lady on the South Side of Chicago".

Its construction has mostly been funded by private donations. (BBC)

•Former US president, Barack Obama and former first lady, Michelle Obama with Illinois governor JB Pritzker at a groundbreaking event at the site in September

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