WASHINGTON (Reuters) -- Warfare high above Earth could litter space with speeding debris that might rip into commercial satellites and space shuttles, the U.S. military's space chief warned on Wednesday.

Air Force Gen. Ralph Eberhart said instant intelligence and communications were so important to the United States and other nations that future enemies might consider blowing up each other's satellites.

"First and foremost, I'm concerned about the debris in space and not knowing what's going to happen once you blow it (a satellite) up," with a projectile, the head of the U.S. Space Command told reporters.

Eberhart said the military was already tracking some 9,000 orbiting objects, some as tiny as a fountain pen, and that commercial satellites and shuttles were threatened by junk moving at thousands of miles [kilometers] an hour.

"Even a [speeding] fleck of paint can ruin your day if you are in the shuttle," he told reporters.

Eberhart, who heads the North American Aerospace Defense Command for the United States and Canada, said the Pentagon was also increasingly worried about the ability of China, North Korea, Iran, Iraq and even "terrorist" groups and drug cartels to disrupt computers using electronic "cyber warfare."

The United States has "become so reliant on our computer systems -- our information -- that as we train and exercise and are involved in contingency operations we have come to take those capabilities...for granted," he said.

The United States is in the process of developing a space policy, including a decision on whether antisatellite (ASAT) weapons should be used in the blackness beyond the atmosphere.

Eberhart said he thinks that destroying another country's communications or spy satellites using a weapon launched into space would be "a last-ditch option."

"I would much rather use negotiations. I would much rather interfere with the uplinks and downlinks, I would much rather...bomb a ground station," Eberhart told reporters.