By KAREN LEIGH, Syria Deeply

As militants from the Islamic State of Iraq and Syria (ISIS) make their way from Mosul to other points in Iraq, the aid needed by hundreds of thousands of newly internally displaced Iraqis threatens to overshadow those of Syrian refugees in Iraq, Jordan, Lebanon and Turkey.

Humanitarian organizations working on the Syrian conflict are already stretched thin and say they are egregiously underfunded. As of June, the U.N. said it had received just 28 percent of the $6.5 billion it needs for 2014, and that a lack of funds had led it to revise its two largest plans for 2014: the Syria Humanitarian Assistance Response Plan (SHARP), serving IDPs, and the Syria Regional Response Plan (RRP), serving those outside.

It also said it has only received 30 percent of the $4.2 billion it has requested in order to meet the basic needs of more than 4 million Syrian refugees by the end of the year.

We asked Andy Baker, Syria crisis response manager at Oxfam, to weigh in on how the crisis in Iraq is already impacting the aid response to Syria.

Syria Deeply: How will the ISIS offensive in Iraq affect the humanitarian situation in Syria?

Andy Baker: I think there are a number of impacts already. It's early days and many people have yet to decide how to respond. There is a refocusing of the world's media on this – Syria was starting to fall off the agenda, so that's good. Now that it's back on the agenda, we need to capitalize on that for advocacy purposes.

The focus on Iraq and the pressure of, What are you going to do about it? has [come at a time] when everyone is still trying to establish what this is all about, and how we will respond. The whole humanitarian community is still in that phase of trying to figure out the shape of this new phase of the crisis.

We've seen an impact on security. We're seeing bombings happening in Beirut and an attempt to destabilize Lebanon. We've seen what feels like a step up in security in Lebanon and Jordan. It feels like there's been a slight tightening by those governments – they're a bit more alert, worried, concerned. Visas are taking longer, there's more scrutiny of people.

There is also a sense of "stretch" among organizational [aid] teams. Many organizations are fairly flat out in this part of the world, and to add the Iraq crisis into this stretches us more, pulls us in more directions.

Syria Deeply: Do you see a possible future where the two crises merge, in terms of donor reaction and aid team response?

Baker: It's difficult to decide at the moment whether these are two separate issues or one issue. At Oxfam we have treated them as separate responses because at the moment in Iraq, the burning issue is about internal displacement of Iraqis. There is the parallel issue of 200,000 Syrian refugees in Iraq. But of course it's part of a wider picture, and how organizations manage that will vary between organizations.

The big question for donors is not how they choose to manage it, but whether they decide to take the same money and spread it more thinly, or allocate new financial resources. And really the big message that we would want to push – that level of need has grown. To push donor countries to consider adding new financial resources to respond [separately] to the Iraq crisis.

Syria Deeply: If the Syria funds were to be further reduced, what would be the first thing to go?

Baker: We already have one example here in Jordan. We've been involved in cash transfer programming, which is a great way to reach vulnerable families and give them the funds they need to pay rent or medical fees or keep their kids in school. And we're ending much of that programming at the end of July. That will be more than 6,000 people who will fall off that system, simply because we can't find new donor resources. Cash programming is an area where donors are beginning to retreat, because it's very expensive.

Some of the other areas, like water, sanitation and hygiene, are hit hard. There's an extraordinary scale of the need – it's massive across Syria, and then Lebanon and Jordan – and now its being impacted by drought. There are huge numbers of people who are used to having running water in their homes who now are having to find new ways of getting water. And there's a risk of disease around that. We've seen polio, measles. We're concerned now about cholera, particularly in the areas of Syria no one is able to access.

Syria Deeply: What will we see from donors over the next couple of months?

Baker: Donors are still trying to figure out exactly how to respond to Iraq, and it feels that perhaps they're holding back a little bit until they see what's going to happen next – rather than getting in very quickly behind the needs of people who've been displaced in the recent fighting in Mosul. Huge amounts of money have not been allocated recently. They're holding back a bit and seeing where this is going.