US President Donald Trump on Wednesday vetoed three decisions by Congress to suspend billions of dollars in arms sales to allies of the United States, including Saudi Arabia and the United Arab Emirates, which are fighting a devastating war in Yemen.    

In a letter to the Senate justifying his use of the presidential veto, Trump said that these decisions "weaken the competitiveness of the United States internationally and harm the important relationships that we share with our allies and partners." 

Trump added that Saudi Arabia and the UAE are bulwarks against "malicious activities" of Iran and its proxies, which are active partners in fighting terrorism in the region, and they also help protect Americans from Iranian-backed attacks on civilian and military installations, including those in areas frequented by state citizens United is like Riyadh airport.

Trump added that failure to provide Saudi Arabia with targeted weapons and precision munitions could prolong the conflict in Yemen and cause more civilian casualties, which will deepen suffering and harm efforts to end the Yemeni crisis.    

This month, Congress approved arms embargoes, in a move that slapped the Trump administration, which took an exceptional course in May by bypassing congressional approval of deals.

Secretary of State Mike Pompeo said the administration was responding to an emergency caused by Iran, the archenemy of Saudi Arabia. But members of Congress, including some Republicans in the Senate, have said there are no legitimate reasons to bypass the Congress, which has the right to reject arms deals.

Observers believe that the arms deals will exacerbate the war in Yemen, as Saudi Arabia leads a US-backed coalition against Iranian-backed Houthis, a war according to the United Nations that has caused the world's worst humanitarian crisis.

This is the third time that the US President has used the presidential veto since he took office.