An unmanned Delta IV rocket took off from Cape Canaveral in Florida with a new intelligence satellite to begin a classified mission on Friday.

The National Reconnaissance Office is keeping details about the capabilities of the satellite secret.

Officials say the launch went off without issue, after it was cleared for take-off.

Friday's launch was delayed a day because of severe weather conditions caused by tropical storm Debby.

The Delta IV is the largest of the Delta-series rockets designed by the aerospace arm of Boeing.