FORT DRUM, US - US President Donald Trump has signed an almost $750 billion defense spending bill, while vowing a new "Space Force" would give America dominance over rivals in China and elsewhere.

"Our competitors have begun weaponizing space," Trump warned troops at Fort Drum in New York state, as he signed a National Defense Authorization 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.

US dismisses 'hypocritical' draft space weapons treaty

The United States voiced strong opposition Tuesday to a treaty proposed by Russia and China explicitly aimed at preventing an arms race in space, calling it "hollow and hypocritical".

A top US official told the global disarmament body in Geneva that Washington had no confidence in the draft Treaty on the Prevention of the Placement of Weapons in Outer Space and of the Threat or Use of Force against Outer Space Objects, or PPWT.

US Assistant Secretary of State for Arms Control, Yleem D. S Poblete, said the US was committed to strengthening the safety, stability and sustainability of space. But she insisted "the draft PPWT is not the right mechanism for accomplishing that".

"Hollow and hypocritical efforts are not the answer," she said, maintaining that the PPWT, first presented by Russia and China in 2008, was "a flawed document". The accusation came as the US eyes creating a Space Force as a new military branch, something President Donald Trump has said would give his country dominance over its rivals.

Russia's representative at the Conference on Disarmament hinted Poblete's criticism of the PPWT might be a smokescreen to divert attention from that project.

"Every time they want to hide intentions, diplomats draw attention to other issues," he said.

Both he and his Chinese counterpart insisted on the good intentions of the draft treaty and urged Washington to collaborate on a text everyone could agree on.

In a heated back-and-forth with the Russian diplomat, US Ambassador Robert Wood insisted the PPWT was "extremely flawed" and beyond repair.

Poblete meanwhile said she was particularly wary of the Russia-backed draft treaty, given "the recent pattern of Russian malign behaviour".

She accused Moscow of "actively pursuing the development and deployment of anti-satellite weapons", and voiced concern over observations of "strange" behaviour by Russian satellites.

"What Russia tells us diplomatically and publicly may be the opposite of what it intends to do with that satellite," she said, pointing for example to the "very abnormal behaviour" of a "space object" deployed by Russia last October.

"The PPWT's proponents, through very careful parsing of treaty language, would allow the very activities they claim to prohibit," she insisted.

Trump ordered the creation of Space Force in June, arguing the Pentagon needs it to tackle vulnerabilities in space and assert US dominance in orbit.

Its creation, however, is not a done deal, as it needs approval from Congress, and the concept has met scepticism from lawmakers and defence officials wary of the cost and added bureaucracy.

But Vice President Mike Pence last week was unequivocal in presenting the administration's wish for it to become a reality - preferably by 2020, the end of Trump's term in office.