The international medical charity Doctors Without Borders says it has not been able to deliver vital medical and humanitarian assistance to the people in the Yemeni capital, Sana’a, due to a tight blockade the Saudi-led military coalition has imposed on the impoverished nation.

Doctors Without Borders, known by the French acronym MSF (Medecins Sans Frontieres), said in a statement on Saturday that for the previous 12 days it had not received authorization from the Saudi-led coalition to fly from Djibouti to Sana'a, which is essential to bring medical supplies and staff to patients in need.

“This has significantly hindered our ability to provide lifesaving medical and humanitarian assistance to a population already in dire need,” said Justin Armstrong, the MSF head of mission in the war-torn country.

The warning came nearly two weeks after Saudi Arabia announced that it was shutting down Yemen’s air, sea, and land borders, after Yemeni Houthi Ansarullah fighters targeted an international airport near the Saudi capital, Riyadh, with a cruise missile in retaliation for ceaseless bombardment of Yemen by the Saudi war machine over the past two and a half years.

The Saudi military, however, announced that it had intercepted the missile, which apparently reached the deepest parts within the Saudi territory.

The MSF further said that though the airport in the southern port city of Aden was partially open to charity flights, it was far from sufficient for the MSF to be able to deliver timely and urgent medical humanitarian aid across the Arab country, since the port was located far away from some of the areas “in most need of humanitarian assistance, and is itself highly insecure.”

“The overall impact of the continuing blockade of other ports and airports increases the strain on the population by the day, at a time when the majority of Yemenis are already struggling with massive increases in food, water and fuel costs, as well as a lack of access to medical care,” the statement said.

On Thursday, three of the United Nations agencies, the World Food Programme, UNICEF and the World Health Organization, in a statement made a fresh plea for the Saudi war machine to remove its blockade on the impoverished nation, warning that without aid shipments “untold thousands of innocent victims, among them many children, will die.”

They further warned that even if the blockade was only partially removed, an additional 3.2 million people would be pushed into hunger. The trio also said that one million children were also at risk of a fast-growing diphtheria outbreak.

Saudi Arabia has been incessantly pounding Yemen since March 2015 in an attempt to crush the popular Houthi Ansarullah movement and reinstate the former president, Abd Rabbuh Mansur Hadi, a staunch ally of the regime in Riyadh.

Latest figures show that the war has so far killed over 12,000 Yemenis and wounded thousands more. The Saudi aggression has also taken a heavy toll on the country's facilities and infrastructure, destroying many hospitals, schools, and factories.

Even the MSF-run hospitals have not been safe from Saudi airstrikes. In August 2016, at least 19 people were killed and 24 others sustained injuries after a Saudi aerial assault hit an MSF hospital in Hajjah’s Abs district. It was the fifth and deadliest attack on an MSF-supported facility in Yemen.

Another 2,100 people have died of cholera since April as hospitals struggle to secure basic supplies across the country.

Certain Arab countries, including the United Arab Emirates (UAE) and Bahrain, are key partners to the deadly Saudi-led campaign, which lacks any international mandate and has faced increasing criticism.