Members of both the US president’s Republican Party and rival Democrats in both Congress and the Senate are hoping to block the sale of the weapons and equipment.
Mr Trump signed the $110bn deal during a recent visit to Saudi Arabia.
“This package demonstrates, in the clearest terms possible, the United States’ commitment to our partnership with Saudi Arabia and our Gulf partners, while also expanding opportunities for American companies in the region, and supporting tens of thousands of new jobs in the US defence industrial base,” a White House statement said shortly afterwards.
But In a letter to the House Foreign Affairs Committee, Congressmen Ted Lieu, a Democrat and Republican Ted Yoho urged their colleagues to reconsider the sale of precision guided munitions (PGMs) to the oil rich Middle Eastern Kingdom.
They pointed out that former president Barack Obama’s administration had halted a planned sale of of PGM’s to Saudi Arabia in December, “due to concerns over the widespread civilian casualties in Yemen” and “significant deficiencies” in the Royal Saudi Arabian Air Force’s (RSAF) targeting capabilities”.
They said: “This decision was the result of an internal review launched after the United Nations and a number of human rights organisations documented a series of RSAF airstrikes on civilian targets including hospitals, markets, schools and a large funeral.”
They added that in March, The State Department had “reversed this policy without providing any justification for what had changed in its assessment.”
As a result they said it was incumbent of the committee to “exercise its oversight powers and to ask tough questions” of Mr Trump’s administration.
In the Senate meanwhile, Senator’s Chris Murphy, Al Franken and Rand Paul introduced a joint resolution of disapproval for the deal.
Under a provision of the Arms Export Control Act, they hope to block the sale of weapons and equipment to the Royal Saudi Air Force, although it represents only a portion of the total package.