Washington DC: A major power outage caused by nearby construction workers plunged the US State Department into darkness on Monday, officials said.
The power cut struck at 9am local time, knocking out lights, computers and phones, and had still not been fully repaired by early afternoon.
In a statement, the State Department said the outage was caused when workers on a nearby construction project severed a power line which supplies the building.
"This has resulted in a power outage at the State Department," spokeswoman Jen Psaki said, adding that emergency systems were fully operational under generator power.
Full power would not be restored for "several hours," Psaki added.
Non-emergency personnel had been relocated to other offices or would telecommute for the remainder of the day.
No special security procedures appeared to have been taken in response to the outage at the building, one of the most secure federal installations in the country.
The United States has the largest diplomatic and consular network in the world, with some 70,000 people working for the State Department.
Several thousand are based at the headquarters in Washington's Foggy Bottom neighborhood.
