Last week, 700 people died in two days in Syria, in what has been described as the deadliest 48-hour period in the country since its conflict began more than four years ago. And 1,700 are reported to have died in the last seven days, in one of the worst weeks on record.

As the global spotlight shifted to Gaza, the past month has been particularly brutal in Syria. Why? Experts cite a bloody fight between Assad forces and the Islamic State of Iraq and Syria (ISIS) for control of the large Shaar gas field, east of Homs; an increased regime offensive in Aleppo; and clashes between ISIS, which is rapidly consolidating its territory in the east, and rebel factions like Jabhat al-Nusra.

Joshua Landis, Editor of Syria Comment and Director of the Center for Middle East Studies at the University of Oklahoma:

Deaths have increased because fighting has increased. ISIS is attacking the regime now and they’re also trying to consolidate, and they’re attacking the other militias. They are on a real tear. The whole of Deir Ezzor province saw lots of fighting this month, and there’s been a lot of fighting in the Kurdish areas as well.

There’s also been a lot of fighting among the more moderate militias, because everyone is jockeying for territory – they want to get their own states. Nusra announced more than a week ago that it was establishing an emirate. And once you do that, you need to fight to gain exclusive authority in your territory. The ISIS declaration of a caliphate caused a domino effect, and there’s a big scramble for northern Syria, which means militias have gone to war with each other.

Theodore Karasik, director of research and development at the Institute for Near East and Gulf Military Analysis (INEGMA):

It seems that ISIS’s advance into Iraq and also its swing back into Syria has ignited other groups to act out on their own. The various Islamic groups are fighting to make gains.

The siege of Aleppo factors in because it has become a main area of power and influence for all sides, and that has catapulted the issue of Aleppo’s future front and center. The death toll is rising rapidly because the nature of the battles is producing higher casualty rates – they’re occurring in urban areas, and during the holy month of Ramadan. For me, an uptick of violence during Ramadan is tied to religious discourse about the significance of [the idea of being martyred during] the holy month.

Under the concept of strategic distraction – [with the world watching] events that are occurring in Gaza and even in the Ukraine – this might be an opportune time [for all sides] to try to make advances, with Syria off the front page.

Faysal Itani, Fellow, the Atlantic Council:

First there’s the uptick of fighting around Aleppo. Both ISIS and the regime have taken on a more aggressive posture there, and the regime has made some significant gains in surrounding areas of the city. With that comes direct casualties, especially from the bombardment campaign that accompanies the operations.

There were also many people killed around the gas field in central Syria, a couple of hundred deaths there. Add to that the fact that as ISIS tries to consolidate in Raqqa and Deir Ezzor, they are going to come into more frequent contact with rival regime and rebel elements.

It’s not only Aleppo – there have been some mainstream rebel operations and breakouts against ISIS in the Damascus suburbs as well. So there are multiple front lines escalating at the same time.

Andrew Bowen, Middle East scholar at the James A. Baker III Institute for Public Policy at Rice University:

Last week you had two heavy days of fighting over the oil and gas facility, and that caused a large loss of life both for the Assad regime and ISIS fighters.

As this conflict becomes more multi-faceted – ISIS versus different groups, and now inner fighting within those groups – the fighting naturally leads to a higher death toll. When you have opposition groups fighting within themselves, civilians become even more vulnerable. They’re not only fleeing fighting between the regime and jihadist groups, they’re now stuck in areas where they could be encountering violence.

So as this conflict becomes more layered, civilians have increasingly limited prospects between leaving the country or being caught in the crossfire. These are the same areas where months ago, they were less vulnerable. In areas that used to be “held” by the opposition, civilians were relatively more secure. And now a lot of those areas are being more contested.

There’s a strategy going on here. Assad is responding to this infighting by allowing it – it’s his interest to allow ISIS to gain ground against the more moderate militias and fighters. It puts him in a stronger position.