In a significant development, the Trump administration on Friday relaxed standards for exporting drones to friendly countries.

Under the new policy, drones that fly at speeds below 800 km per hour are no longer subject to the Missile Technology Control Regime (MTCR).

"This action, which is consistent with the MTCR guidelines will increase the US's national security by improving capabilities of its partners and increase economic security by opening the expanding drones market to the US industry, White House Press Secretary Kayleigh McEnany said in a statement.

This policy change modernises our approach to implementing our MTCR commitments. It makes it more reflective of the technological realities, Assistant Secretary of State for Political Military Affairs Clarke Cooper told reporters during a conference call.

It helps our allies, it helps our partners - it helps them all meet their urgent national security and commercial requirements, and it also advances the US's national security and economic interests, he added.

Cooper, however, said higher-speed systems such as cruise missiles, hypersonic aerial vehicles, and advanced unmanned combat aerial vehicles are not affected by this revision.

The United States remains a committed member of the MTCR and holds it as an important non-proliferation tool to curb the spread of high-end missile technologies to countries such as North Korea and Iran.

Preventing the use and spread of the weapons of mass destruction and their means of delivery remains a Trump administration priority, he said.

As of now only three countries -- England, France and Australia -- are allowed to buy larger, armed drones from US manufacturers.

In a statement, the White House said while the missile control pact is critical in slowing proliferation and promoting peace and security, it is in dire need of modernisation as it applies to unmanned aerial systems (UAS).

In a sector of rapidly evolving technology, the MTCR standards are more than three decades old, McEnany said, adding that not only do these outdated standards give an unfair advantage to countries outside the MTCR and hurt the United States industry.

They also hinder our deterrence capability abroad by handicapping our partners and allies with subpar technology, he asserted.

More than two years of discussion with MTCR partners were unable to produce consensus on this overdue reform, she added.

Senator Jim Risch, chairman of the Senate Foreign Relations Committee, said for too long, the restraint of the international community with regard to exports of large unmanned aircraft has created an opportunity for the Chinese military to advance its defence technology and industrial base, and build new defence relationships around the world, including with traditional US partners.

I commend the administration for its robust, years-long diplomatic effort to modernise the MTCR to account for China's actions. It has become clear, however, that one MTCR member state will inevitably block any consensus within the regime on necessary changes. Therefore, the United States has no choice but to make the policy changes that the administration has outlined today, he said.

However, Senator Bob Menendez, Ranking Member of the Senate Foreign Relations Committee, alleged that the Trump administration has once again weakened international export controls by this action.

It is important to appreciate that the Missile Technology Control Regime originally adopted stringent controls on exports of advanced drones at the urging of the United States. To disregard this policy now is likely to undermine the credibility and influence of the MTCR generally, which also coordinates international controls on the sale and spread of dangerous ballistic missiles and technology around the world, he said.

Trump is unilaterally abrogating a long-standing arms control agreement because it is inconvenient for his anything goes' policy to sell dangerous weapons seemingly anywhere to anyone, alleged Congressman Eliot Engel, Chairman of the House Foreign Affairs Committee.

In this case, it is the MTCR, set up by President Reagan, to restrict exports of unmanned aerial vehicles that can carry nuclear weapons. Trump wants to be free to sell UAVs that can carry heavy warheads, bombs, and other explosive devices more than 300 km, he alleged.