As a Saudi Arabia-led military campaign in Yemen entered its seventh day on Wednesday, international organizations and relief agencies expressed alarm at the rising number of civilian deaths, many of them children, and the increasingly dire humanitarian crisis unfolding.

“The attacks on hospitals and medical facilities by warring factions as well as the deliberate targeting and destruction of private homes, education facilities and basic infrastructure cannot be tolerated,” EU foreign policy chief Federica Mogherini and EU humanitarian aid commissioner Christos Stylianides said in a joint statement.

Saudi Arabia, in coordination with a number of Arab Sunni-majority states, began launching airstrikes in Yemen last week in an attempt to roll back territorial gains by Shia rebels it says are backed by Iran.

The rebels, called Houthis, have twice displaced Yemen’s internationally recognized president, Abd Rabbu Mansour Hadi — first from the capital Sanaa, which they overran in September, and then the southern port city of Aden, which they are currently attempting to seize.

Former Yemeni president Ali Abdullah Saleh, deposed in a 2012 revolution, has lent his support and influence among Yemen’s armed forces to the Houthis in a bid to regain control.

Amid the relentless airstrikes and ground battles between Houthis, their allies and Hadi loyalists, relief agencies are struggling to meet the humanitarian needs of civilians caught in the crossfire.

“There have been airstrikes in the north, west and south, and clashes between opposing Yemeni armed groups in the center and south, that are putting immense strain on already weak medical services," Cedric Schweizer, an aid worker in Yemen with the International Committee of the Red Cross (ICRC), said in a statement.

The ICRC said on Tuesday that the Saudi-led coalition had prevented it from delivering much-needed medical supplies to affected civilian areas.

Underscoring the dangers Yemeni civilians face, an explosion at a dairy facility near the city of Hodaidia on Wednesday killed at least 25 people, according to medical sources who spoke to Reuters. Conflicting reports have pinned the blame on both coalition airstrikes and Houthi rebels.

Since the airstrikes began last Thursday, more than 100 civilians, including at least 62 children, have been killed, medical officials said.

“Children are in desperate need of protection, and all parties to the conflict should do all in their power to keep children safe,” said Julien Harneis, a Yemen representative for UNICEF.

Leila Zerrougui, the special representative of the United Nations Secretary-General for Children and Armed Conflict, said on Tuesday: “I am alarmed by the rising number of child casualties in Yemen ... We cannot tolerate seeing them victims of this conflict.”

Humanitarian groups say that Yemen is at least partially under a blockade at the moment due to the fighting and that desperately needed supplies are not reaching their destination.

“MSF [Doctors Without Borders] is currently unable to deploy additional emergency medical staff to Yemen, where they are badly needed,” said Dr. Greg Elder, director of operations for the organization. “We urgently need to find ways to get humanitarian relief and personnel inside the country.”

Since fighting intensified last week, aid and relief organizations that were already operating in the impoverished and war-torn country saw personnel flee for safety.

“Very few humanitarian actors have stayed in the country, while the needs are actually getting greater, and so more supplies and human resources are required on the ground,” Dounia Dekhili, program manager for Doctors Without Borders, said in a statement. “With the conflict continuing, the risk of facing a shortage of drugs and medical supplies is real.”

The conflict is also taking its toll on access to food. Yemen is one of the most food insecure countries in the world, with over 40 percent of its inhabitants dependent on food aid, and more than 90 percent of its total food coming from imports.

Now, many food relief organizations and workers are reporting that the fighting is threatening those supplies. The U.N.’s Food and Agriculture Organization (FAO) told Reuters on Wednesday that existing stocks are at risk of not being replenished.

“Although government sources reported sufficient stocks to last the country about six months, the conflict will likely negatively impact distribution, market availability and prices of foodstuffs sooner than earlier expected,” Salah ElHajj Hassan, FAO’s representative in Yemen, told Reuters on Wednesday.

Though political in nature, the fighting between Houthis and Hadi loyalists and allies seemed to be taking on an increasingly sectarian element as a result of the foreign intervention.

The Houthis, who adhere to the Zaydi branch of Shia Islam, are viewed by Saudi Arabia and other Sunni Arab countries as an extension of Shia Iranian influence in the region, but the extent of Iranian support is disputed.

Iran has denied providing weapons and training to Houthis, but confirmed on Tuesday that it sent shipments of food, medicine and other aid to rebel-controlled areas.

The Saudi-led coalition has pledged to press on with its military campaign until its goals are met, but it was unclear whether airstrikes alone would suffice. Despite the bombings, Houhti fighters pressed ahead on Wednesday into Aden.

According to Agence-France Presse, Riyadh Yassin, the foreign minister for Yemen’s internationally recognized government, said on Wednesday that “at some stage airstrikes will be ineffective” and called for the introduction of ground troops.