Aleppo, Syria
Damage is seen on Khan Wazir street, which faces Aleppo's historic citadel controlled by forces loyal to Syria's President Bashar al-Assad, in Old Aleppo as rebel fighters claim to have advanced in the area July 22, 2014. REUTERS/Sultan Kitaz

More than 1,700 people were killed in Syria this week, in what has been described as the bloodiest seven days since the civil war began more than three years ago. The mostly-Sunni militant group Islamic State (IS), formerly known as Islamic State in Iraq and Syria, is accused of killing at least 250 government soldiers and civilians in a gas field near Homs City in just one battle. Damascus saw its fiercest battles in months, and 700 people were killed in just 48 hours across the county. This all took place in the nine days since President Bashar al-Assad was sworn in as for a third term on July 16.

While IS was responsible for a lot of the bloodshed, experts at Syria Deeply say there has been increased fighting between smaller rebel groups who also oppose Assad’s regime. IS is seeking to eliminate its rivals, or force them to pledge allegiance, and other rebel groups want IS out altogether.

According to Britain-based organization Syrian Observatory for Human Rights, the fighting has now claimed 170,000 lives, with hundreds of thousands more people displaced.

"Civilians have increasingly limited prospects between leaving the country or being caught in the crossfire," Middle East scholar Andrew Bowen told Syria Deeply.

Last month IS declared a caliphate in Northern Syria and Iraq, where it has already taken control of Mosul and several other cities. The Caliphate is said to be led by Abu Bakr al-Baghdadi, who calls himself Caliph Ibrahim.

Last week, the United Nations released a report accusing IS of potential war crimes in Iraq, specifically the targeting of children.

“The deliberate or indiscriminate targeting of civilians, the killing of civilians, the use of civilians as shields, the hindering of access for civilians to humanitarian assistance may amount to war crimes or crimes against humanity,” the report said.

Since June, when IS found a strong foothold in Iraq, international attention has been focused there -- and then on Gaza, Israel, Ukraine, Russia and a heartbreaking series of plane crashes. And while the world was looking elsewhere, Syria slipped even further into despair.