Saudi Arabia announced Tuesday that it was ending the nearly one-month-old air assault it spearheaded against the Houthi rebels and their supporters throughout Yemen. Saudi coalition spokesman Brigadier General Ahmed Al Asiri told reporters that the operation concluded “based on a request by the Yemeni government and President Abd Rabbuh Mansour Hadi.”

Saudi Arabia and its coalition partners, backed by the US, have been dropping bombs on targets throughout Yemen for the last four weeks with the aim of defeating the Houthi rebels, who have taken control of most of the country’s western provinces.

The United States government facilitated the continuous assault by providing the coalition with logistical and intelligence support, approving possible targets and refueling jet fighters after bombing raids. The Saudi monarchy and the US government have been expressly seeking the reinstatement of President Hadi, who fled the country for Riyadh in the face of a Houthi assault at the end of last month.

Asiri told reporters that sustained air strikes were no longer necessary, claiming that they had effectively neutralized the Houthis as a threat. He did not rule out future strikes, and stated that military force would continue to be used prevent the Houthi militia from “moving and carrying out any operations” in Yemen.

With the conclusion of the air campaign the Saudi spokesman announced the beginning of “Operation Restore Hope,” aimed at achieving a “political solution” in Yemen and escalating “anti-terrorist” operations inside Saudi Arabia.

The campaign of intense air strikes has been ineffective in weakening the Houthis, who remain in control of a majority of the country’s western provinces and major urban centers, including the capital of Sanaa and portions of the southern port city of Aden. The Houthis have gained an advantage partly because of support from military forces loyal to the former longtime dictator Ali Abdullah Saleh and his son Ahmed.

Despite their limited impact, a press release from the Saudi Defense Ministry claimed that military operations over the last four weeks had “successfully managed to thwart the threat on the security of the Kingdom of Saudi Arabia and neighboring countries through destruction of the heavy weapons and ballistic missiles seized by the Houthi militias and troops loyal to Ali Abdullah Saleh, including bases and camps of the Yemeni army.”

According to an official estimate from the United Nations, the Saudi air campaign, in addition to fighting on the ground, killed at least 944 people and wounded a further 3,487 between March 19 and April 17. Many of the casualties have been civilians, including women and children, killed when air strikes in residential areas destroyed their homes.

Two air strikes on Tuesday killed approximately 40 people, mostly civilians. A strike on a bridge in Ibb province killed at least 20 people, while an air strike in the northern city of Haradah killed 13 civilians and seven soldiers. The death toll from the bombing of a weapons depot that flattened a residential neighborhood in Sanaa on Monday was raised to 38. The Houthi-controlled Interior Ministry reported that in all 84 people were killed by air strikes throughout the country Monday.

Prior to Tuesday’s announcement of the end to the air campaign, Saudi King Salman bin Abdulaziz Al Saud announced the mobilization of National Guard troops to support military operations in Yemen. The Saudi-led coalition has raised the possibility of a ground invasion, aimed at pushing the Houthis out of southern Yemen and back to their northern home province of Saada.

Meanwhile, US warships, including the aircraft carrier USS Theodore Roosevelt, remain off the coast in the Gulf of Aden, in position to block a convoy of Iranian cargo ships allegedly seeking to deliver aid to the Houthis. US officials have accused Iran of backing and arming the Shiite rebels. The UN Security Council voted last week, with Russia abstaining, to impose an arms embargo on the Houthi rebels.

Speaking to reporters on Tuesday, White House Press Secretary Josh Earnest insisted that the US was committed to blocking any possible arms shipments to the Houthis. “The United States alongside the international community, including the United Nations, is serious about the Iranians not providing weapons to the Houthis,” he stated. “Providing weapons to the Houthis only exacerbates the violence and instability in this region in a way that will have continued terrible impact on the humanitarian situation in the country.”

As the Saudi-led operations entered a new phase Tuesday, the World Health Organization (WHO) released a statement warning that Yemen, already deeply impoverished prior to the Saudi assault, faces the “imminent collapse” of its health care system.

Fighting on the ground, as well as a naval blockade being enforced by the Saudi-led coalition and the US, has resulted in a serious shortage of medical supplies, clean drinking water and fuel. Aid flights have been limited by a no-fly zone enforced by coalition warplanes over the country, creating the conditions for a potential health catastrophe.

Vital power infrastructure throughout the country, necessary for pumping clean water from underground aquifers, has been knocked out, contributing to a deepening of the shortage of clean drinking water in the country.

Dr. Ahmed Shadoul, the WHO Representative for Yemen, stated that over the last four weeks the number of cases of bloody diarrhea in children under the age of five had doubled due to a lack of access to clean drinking water. He also reported that there had been an increase in cases of measles and malaria, in addition to heightened rates of malnutrition among women and young children.

The WHO statement warned that power cuts threaten the country’s blood banks and vaccine stockpiles. The loss of Yemen’s vaccine stockpile would increase the risk of the widespread outbreak of communicable diseases such as measles and polio.

The lack of electricity or fuel for generators has severely hindered the maintenance of crucial hospital operations throughout Yemen. According to the WHO, without the return of consistent power, kidney dialysis as well as cardiac and cancer treatment programs are threatened with complete collapse.