A major thoroughfare in the downtown core is closed due to a demonstration by thousands of Tamil protesters.

University Ave. is closed from Dundas St. to Queen St. At one point, it was closed from College St. to King St.

Queen and Dundas Streets, which had been closed, are now being reopened, police say.

Commuters are being urged to avoid the area. Those taking streetcars which pass through the affected area are advised to leave themselves extra time.

The closures are in close proximity to several hospitals, including the Hospital for Sick Children. Emergency vehicles are able to squeeze through the protesters.

Protesters started congregating outside of the U.S. Consulate early Sunday evening. Crowds stayed throughout the night, growing larger as the morning wears on. The numbers subsided after the rush hour.

The demonstrators are demanding U.S. President Barack Obama intervene to stop what they call a continuing genocide in Sri Lanka.

A similar protest in Ottawa on Parliament Hill brought out nearly 33,000 Tamil supporters.

The protesters called on Canada to do more to force the Sri Lankan government to end an offensive against the last stronghold of the Tamil Tigers.

With files from The Canadian Press.