The official, who asked not to be named, said there was no immediate word on any casualties or damage from the blast, which followed a series of suicide attacks in Kabul earlier this month.
It was not immediately clear whether the embassy, which is located near other foreign missions, was specifically targeted.
Obama says six US troops killed in Afghanistan attack were 'outstanding'
Following talks in Islamabad last week, officials from Afghanistan, Pakistan, the United States and China are due to resume meeting in Kabul on Monday to try to agree a roadmap for a negotiated settlement with the insurgents.
The Taliban, increasingly successful on the battlefield since international troops ended most combat operations in 2014, have yet to agree to take part in the process
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ