A capsule on a first privately-run resupply mission successfully linked up Wednesday with the International Space Station, the US space agency NASA said.

A robot arm operated by two of the six astronauts aboard the space station snatched the Dragon capsule at 1056 GMT, more than thirty minutes ahead of schedule, it said.

The docking will be completed after the ISS crew first inspects the capsule's condition with the help of cameras, a task that was expected to take another two hours, a NASA television announcer said.

SpaceX, the private company owned by billionaire entrepreneur Elon Musk, launched the Dragon Sunday evening atop a Falcon 9 rocket from an air base in Cape Canaveral, Florida near the Kennedy Space Center.

The mission was the first of a dozen ISS supply runs that NASA has contracted out to SpaceX under a four-year, $1.6 billion contract, fulfilling a role once carried out by NASA's now retired shuttle fleet.

The capsule is loaded with 882 pounds (400 kilograms) of equipment and material for scientific experiments that will be conducted by an ISS crew commanded by American astronaut Sunit Williams.

The cargo also includes food, clothing and other necessities for the international crew, which besides Williams includes three Russians, a Japanese and another American astronaut.

Dragon is currently the only spacecraft capable of ferrying cargo from the space station back to Earth, and on its return voyage scheduled for October 28 will carry back 1,240 pounds (562 kilograms) of equipment and material.

It is supposed to land by parachute off the coast of southern California.