The unmanned Dragon capsule from the private US firm SpaceX successfully reached the International Space Station Sunday, its third trip carrying supplies and equipment to the orbiting lab.

NASA television broadcast live images of the ISS's 17.6 meter (57.7 foot) long robotic arm as it grabbed hold of the gumdrop-shaped capsule on schedule at 11:14 GMT.

"Capture complete, congratulations to the entire team," said the Japanese station commander, Koichi Wakata, who was in charge of operating the mechanical arm along with American Rick Mastracchio.

"We're excited," Wakata said, smiling.

Both astronauts were dressed casually in polo shirts as they carried out the procedure.

NASA said the event took place 250 miles (402 kilometers) above the Earth's surface as the ISS hovered over the Nile river.

The operation to berth the Dragon to the ISS's Harmony module, a US-built utility hub, begins at 13:30 GMT, NASA said.

SpaceX has a $1.6 billion contract with NASA for a series of future supply missions.

This marks the California-based company's third commercial resupply mission and fourth visit to the ISS.

After three delays, a SpaceX Falcon 9 rocket blasted off with the Dragon capsule at 3:25 pm (1925 GMT) from Cape Canaveral in Florida on Friday.

The mission had originally been scheduled for mid-March but did not go ahead because of technical issues.

The Dragon capsule is due to deliver 2.2 tonnes of cargo, including food, new spacesuits, components to replace those aboard the ISS and equipment for 150 scientific experiments.

One of the experiments will be the Vegetable Production System, or Veggie, which would allow the production of salad-type crops to safely feed the astronauts.

Another experiment seeks to determine why an astronaut's immune system weakens in microgravity.

NASA is also sending an experiment system that can more rapidly transmit data using a laser communication system, in a first from space.

In all, SpaceX is due to complete 12 missions for the US space agency.

SpaceX became the first commercial entity to reach the space station with its Dragon cargo ship in May 2012 in a trial run. Owned by Internet entrepreneur Elon Musk, the company's first cargo mission took place in October that year.

The last mission involving a Dragon capsule was completed in March 2013.