Blackwater, a U.S. security contractor operating in Iraq, is partly back on the job there days after a shootout that left 11 Iraqi civilians dead.
The company provides security to all US state department employees in Iraq.
It had been ordered by the Iraqi government to halt operations while a joint US-Iraqi inquiry was held.
A US embassy spokeswoman said the decision to allow Blackwater to resume work had been taken in consultation with the Iraqi government.
The spokeswoman, Mirembe Nantongo, said Blackwater operations would be limited to essential missions only outside Baghdad's heavily-fortified Green Zone.
A separate Iraqi interior ministry investigation has found that Blackwater was “100% guilty” of the incident in which 11 Iraqi civilians were killed.
Blackwater says its guards acted in self-defence, but this has been disputed by Iraqi eyewitnesses.