The United States has vowed to develop a new "Space Force" that would give America dominance over rivals in China and elsewhere.
US President Donald Trump on Monday signed an almost $750bn defence spending bill and pledged to make America a leader in space warfare.
"Our competitors have begun weaponising space," Trump warned troops at Fort Drum in New York state, as he signed a National Defence Authorisation Act passed by Congress earlier this month.
"It's not enough to have American presence in space. We must have American dominance in space," Trump said, as he warned of the threat from China and elsewhere.
"Look at what they're doing, they have given me run-downs," he said in reference to security briefings. "I've seen things that you don't want to see what they're doing and how advanced they are.
"They want to jam transmissions which threaten our battlefield operations and so many other things.
"We'll be catching them very shortly," he said. "We will be so far ahead of them in a very short time, your head will spin."
He specifically mentioned a "new" Chinese military division that oversees space operations.
The spending bill contains a number of important provisions, including a prohibition on delivering F-35 Joint Strike Fighter aircraft to Turkey, a Nato ally unless they ditch Russian technology.
Trump has sparred with the country's leaders over the detention of a Christian pastor.
It also extends a restriction on US-Russian military cooperation, something the White House vociferously opposed.
The defence policy spending bill is aimed at modernising the military and improving readiness.
The bill is "the most significant investment in our military, and our war fighters in modern history," Trump said.
It will be used to replace ageing tanks, planes and ships "with the most advanced and lethal technology ever developed," Trump said. "And hopefully, we'll be so strong, we'll never have to use it, but if we ever did, nobody has a chance."
The bill authorises spending for 77 F-35 new fighter jets, a new aircraft carrier and other battle force ships and for modernising the US nuclear triad, the White House said in a statement.
It also provides a 2.6% pay raise for members of the armed services - the largest in nine years, the White House said - and grows the size of the US armed forces by allowing an increase of
15,600 troops and sailors.
The bill also authorises $500mn for the co-production of Israel's missile defence systems, $850mn to train and equip Iraqi Security Forces and 250mn in security assistance for Ukraine.
It covers spending for the fiscal year 2019, which starts October 1.
