Barack Obama. Photo by EPA/BGNES
A letter addressed to US President Barack Obama and containing a "suspicious" substance, has been intercepted outside the White House, informed world agencies.
The letter has been halted by the service that inspects all postal deliveries to the presidential office, said the US Secret Service.
The news comes hours after the interception of a letter addressed to US Republican Senator for Mississippi Roger Wicker, which was tested positive for the deadly ricin poison.
According to NBC news quoting responsible officials, the letter sent to President Obama came from the same sender and also contained ricin.
It also comes days after the Monday bombing at the Boston marathon, which left 3 people dead and scores injured, including some in critical condition.