After an Israel airstrike killed World Central Kitchen aid workers in Gaza, international humanitarian agencies say they continue to face violence and practical obstacles trying to deliver aid throughout the famine-threatened territory.

UNICEF spokesperson Tess Ingram tells TIME in a phone call from Rafah on Sunday about a harrowing and unsuccessful attempt to get aid to north Gaza a week after the World Central Kitchen attack. The convoy she was traveling in, which had coordinated in advance with the Israel Defense Forces, encountered gunfire while waiting at a checkpoint. Ingram says she doesn’t know who fired the shots, but they seemed to come from the direction of the checkpoint, which she estimates was less than a kilometer (roughly half a mile) away.

Delays. Access restrictions. Shooting.On Tuesday, UNICEF’s humanitarian convoy was hit by live ammunition on the way to deliver life-saving aid to north Gaza.Our staff are safe, but the immense difficulties of delivering aid are making it nearly impossible to meet children’s… — UNICEF (@UNICEF)

The IDF tells TIME in a statement that after an examination, it appears its forces “were not within firing range of the convoy at the time and place indicated and it was found that no fire was carried out at the vehicle by the IDF,” adding “the IDF works in order to prevent harm to humanitarian teams.”

In response, Ingram says “we think it’s important that an independent investigation is conducted to shed light on what happened and to ensure that in the future, we’ve got the necessary security to deliver aid.”

The need is dire. The world’s authority on food insecurity last month that one million people face a looming famine in Gaza. The Hamas-run health ministry reported 28 children of malnutrition and dehydration as of April 12.

Despite the needs, more than half of recent requested aid missions to north Gaza were unsuccessful, the U.N. Office for the Coordination of Humanitarian Affairs. Between April 6 and 12, Israel facilitated 41% of missions, with 41% denied or impeded including due to hostilities, and 17% canceled by aid groups mainly due to logistical constraints.

Even coordinated missions can be dangerous, with World Central Kitchen saying it coordinated with Israel before the military attacked its convoy on April 2. The resulting deaths of seven aid workers, which Israel called a prompted President Joe Biden to Israel––increase food aid into Gaza and take measures to protect civilians or risk losing U.S. support.

Israel it would open new avenues to allow in more aid, including a COGAT, the IDF’s humanitarian arm, tells TIME in an email that it has increased aid, with more than 300 trucks entering Gaza each day last week.

Biden that the number of trucks was still “not enough.” Data from , the U.N.’s Palestinian relief agency, shows only a slight uptick (the agency counts trucks differently than COGAT, ). COGAT accused the U.N. of not collecting aid, on X of items lined up inside Gaza and saying: “The bottlenecks are not on the Israeli side.”

The U.N.’s head has that “the real problem is that the way Israel is conducting this offensive is creating massive obstacles to the distribution of humanitarian aid,” with bombardment and combat threatening workers. Since the war began on Oct. 7, 217 aid workers have been killed in Gaza, according to the Aid Worker Security Database.

“The increase in aid is not yet tangible, sustained or uninterrupted,” “Aid also needs to reach safely all those in need.”

Here’s what Ingram tells TIME about the challenges to delivering aid and the needs. The interview has been condensed and edited for clarity.

What happened on Tuesday at the checkpoint?

What happened was we hit the road––we were quite late in getting the green light to leave––we drove up toward the Salah Al-Din checkpoint on the Wadi Gaza line. We were instructed to wait in the designated holding areas for convoys, which is not unusual. While we were in that holding area, gunfire broke out.

Do you know what instigated it or where it came from?

I don’t know what instigated it. It seemed to come from the direction of the checkpoint, towards the south, and it seems to be towards civilians, or apparent civilians, who then turned and ran in the other direction. I would say I saw a dozen (apparent civilians).

Can you describe the impacts on your convoy from the gunfire?

We were a convoy of three cars and two trucks. Only one vehicle was hit, that was the one I was in. We received three bullets, one in the hood of the car, and two on the door where I was sitting, which was the back passenger door on the right hand side, one in the window and one in the door. My colleague in one of the other cars, he saw bullets ricocheting off the ground. Ahead of us at the holding point there was another U.N. convoy from the World Food Programme and the United Nations Office for Project Services. They had a bullet go through the windshield of their fuel truck.

We’re very fortunate that we were in an armored vehicle…Fortunately, we were unharmed.

What happened after the gunfire ?

We decided that we would continue with the mission. And basically, that just meant continuing to hold until we got the green light. Unfortunately, we held there for at least another two hours. And by that point, it was about 1 p.m., the mission was no longer feasible, because we knew that if we got the green light, we would have still had to make the journey to the checkpoint, through the checkpoint, up north, and we wouldn’t have the time needed to complete the mission. So we decided that we would turn back and try another day.

Today, we had our redo of our mission to the north. It was a 13-hour mission, and almost six of those hours were spent waiting for the green light. We didn’t get to complete everything, and that’s really disappointing. We were only able to conduct the nutrition and medical aspects of the mission at Kamal Adwan Hospital. We had 45 minutes on the ground at the hospital, that’s it.

We delivered a whole truck of medical and nutrition supplies. It included ready-to-use therapeutic food, which is a treatment for malnutrition, and high energy biscuits.

What did you see people experiencing on the ground in North Gaza?

The level of destruction is mind blowing. It includes the roads, it includes a large percentage of the buildings. There were people on the streets, but we had no issues in terms of mobbing or looting. People were actually waving and smiling at us, which I find so admirable considering that they’ve been through six months of horror and war in the north of Gaza.

(At the hospital) we went to the children’s ward and met some mothers and some children. I met three children who suffered from malnutrition––a 35-day-old baby, a two-and-a-half year old, and a seven-year-old. They all had severe acute malnutrition. The mothers were very distressed. The seven-year-old wasn’t able to speak and she was very, very thin. The 35-day-old baby was one and a half kilos (three pounds). The two-year-old was four kilos (nine pounds).

We evacuated that seven-year-old girl from the north to the south, we just dropped her off at a stabilization center in Rafah. Her mom said that they had run out of food and were having to eat animal fodder, and it made her daughter very sick.

What do you see as the biggest challenges to delivering aid?

The biggest challenges are the access and the security environment. Even when we have access approved, it’s unpredictable and unreliable. And then when we do get access, the environment is still very dangerous. So those two things combined––the unpredictable access and the insecurity––really hamper our ability to reach people and deliver the much needed assistance.