Washington has tentatively approved the sale of battle tanks, hundreds of machine guns and equipment to Saudi Arabia. The $1.15 billion (1.03 billion euros) deal comes as Saudi-led airstrikes resume in Yemen's capital.
The US State Department said Tuesday it had approved the potential sale of more than 130 Abrams battle tanks, 20 armored recovery vehicles and other equipment to Saudi Arabia.
"This proposed sale will contribute to the foreign policy and national security of the United States by helping to improve the security of a strategic regional partner which has been and continues to be a leading contributor of political stability and economic progress in the Middle East," the US Defense Security Cooperation Agency said in a statement.
US arms manufacturer General Dynamics will be the main beneficiary, the statement noted.
Saudi military intervention in Yemen continues
The approval for land force equipment coincides with Saudi Arabia leading a military coalition in support of Yemeni forces loyal to the exiled government of President Abed Rabbo Mansour Hadi, who are trying to oust Iran-allied Houthi forces from the capital, Sanaa.
Human rights groups have called on the United Nations General Assembly to suspend Saudi Arabia from the UN Human Rights Council until the military coalition stops killing civilians in Yemen.
"The Saudi-led coalition's campaign in Yemen has been devastating for civilians," Human Rights Watch researcher Kristine Beckerle said. "The US should be suspending arms sales to Saudi Arabia, not approving more."
Rights groups, UN register concern
The UN says more than 6,400 people, mostly civilians, have been killed since the coalition air campaign began in Yemen last March.
"The reported escalation in fighting exacerbates the already dire humanitarian and human rights situation and the suffering of the Yemeni people," UN deputy spokesman Farhan Haq told reporters Wednesday in New York
In Washington, US State Department spokeswoman Elizabeth Trudeau said that US diplomats were "very concerned" by recent civilian deaths in Yemen, including an airstrike on a potato chip plant, but she did not directly comment on concerns that US weapons being sent to Saudi Arabia could be used against civilians in Yemen.
"We regularly talk to our partners and our allies around the world," Trudeau said Tuesday. "You know, civilian casualties are obviously of grave concern to us."
Civilian deaths in Yemen continue
In Sanaa, the Al-Aqel potato chip plant's director, Abdullah al-Aqel, told the AFP news agency that Tuesday's airstrike had killed 16 factory workers and left 10 others wounded when the food processor was struck overnight.
US lawmakers will have 30 days to review the arms sale before any weapons can be transferred. US Senator Chris Murphy said in a statement that he was concerned about the high civilian casualty rate in Yemen.
The Democratic Party member from Connecticut said Saudi Arabia had "largely backed away from" the fight against Islamic State militants "and I'd like to see them commit to rejoin that fight as part of major new military sales."
His concern was echoed by Senator Rand Paul, a Republican from Kentucky, who vowed to cross party lines to block the deal.
Iran, which backs the Houthi rebels in Yemen, called on Saudi Arabia to end airstrikes. In Tehran, foreign ministry spokesman Bahram Ghasemi said Wednesday that world powers are failing to act upon Riyadh‘s "continued destruction of the infrastructure of this country, killings of civilians and brazen, inhumane siege of an oppressed nation."
The United States approved a $1.29 billion deal to replenish the Saudi air force last November after it had depleted much of its arsenal in the bombing campaign in Yemen. Saudi Arabia is one of the region's top importers, sourcing weaponry from US and European manufacturers that ultimately is used to wage campaigns in Yemen and Syria.