"We strongly encourage US citizens to maintain a high level of vigilance, be aware of local events, and take the appropriate steps to bolster your personal security," the Overseas Security Advisory Council (OSAC) said in a statement.
"Due to information about an imminent security threat against the US consulate compound, the US Consulate General Istanbul advises all US citizens to avoid the US consulate today," said the OSAC, which promotes security cooperation and information-sharing between US businesses and the State Department.
The warning comes just three days after a couple shot 14 people dead in a rampage in San Bernardino, California. Today the Islamic State group praised the perpetrators as "soldiers" of its caliphate.