Building operations have been halted at the Obama Presidential Center after a noose was found on site.
The three-building campus is being built in Jackson Park, on the south side of Chicago.
Barack and Michelle Obama attended the ground-breaking event for the site in September last year, with the $500 million project set to open in 2025.
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Plans for the centre were seemingly running smoothly, with the former president's foundations saying that the site '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'.
Construction has been funded by private donors and is being carried out by Lakeside Alliance, a collection of black-owned construction firms.
However, when a noose was found on-site construction was halted, with Lakeside Alliance saying that the incident had been reported to the police and they 'will provide any assistance required to identify those responsible'.
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"We have zero tolerance for any form of bias or hate on our worksite. Anti-bias training is included in our onboarding process and reiterated during site-wide meetings. We are suspending all operations on site in order to provide another series of these trainings and conversations for all staff and workers," they added.
And as a reward to find whoever is responsible, the Alliance is offering $100,000 (£85,000).
The Obama Foundation also responded to the incident with a statement: "This shameless act of cowardice and hate is designed to get attention and divide us. Our priority is protecting the health and safety of our workforce."
The Governor of Illinois, JB Pritzker, also spoke out about the situation on Twitter, writing: "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."
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Sargent Rocco Alioto, a spokesperson for the Chicago police, has said that the incident is currently under investigation but it is not clear how long the pause will last.
Despite the incident, the Obama Presidential Centre is set to be an 'embodiment of hope' for the city.
Conceived with the aim of 'creating jobs, driving economic opportunity, and unlocking the potential that has always existed on the South Side. By tapping into the boundless talent of neighborhoods throughout Chicago, it will become a campus for the community, built in partnership with the community'.
The site will feature a museum, winter garden, library, forum, plaza, park, and play areas.
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Of particular note is the winter garden, which was built in honour of Hadiya Pendleton, a Chicago teen who was shot and killed eight days after performing in the majorette squad for President Obama's second inauguration.
Topics: Barack Obama, News, US News, Racism