The enemy of an enemy is not always an ally, at least not in Syria. Terrorist groups associated with al-Qaeda have faced a new wave of opposition in both Syria and Iraq this week, as rebel and tribal groups have turned on their sometime "friends."

In Syria, The Guardian reports, groups opposed to Syrian president Bashar al-Assad have escalated their attack against Islamic State of Iraq in Syria (ISIS) in two of the jihadist group's strongholds. Most of the ISIS fighters, who are typically not Syrians, came to the country fight against Assad in the hopes of knocking out the government and establishing an Islamic state. As their strength has grown, and their tactics have become more brutal, they've found themselves clashing with other rebel fighters as much as they have the military. The fighting near Aleppo seems to end a months-long coexistence of necessity between the two rebel factions. The Guardian explains: 

The group's members have imposed a strict interpretation of Islamic law in much of northern Syria, subverting local authority and intimidating towns and communities. The increasing strength of the group has also further splintered the original armed Syrian opposition, which has at times come to a battlefield accommodation with the better funded jihadis, and had tried to avoid a reckoning with them.

According to the LA Times, the fighting started on Friday after ISIS attempted a takeover of Atarib, near Aleppo. A coalition of Free Syrian Army fighters, with help from Islamic Front rebels, responded by blocking ISIS members from entering the town, and captured a couple dozen ISIS members in the process. There doesn't seem to be an accurate death toll from Friday's fighting, which soon spread to a handful of other cities around Aleppo. 

Meanwhile, a coalition of government forces and tribal militias in Iraq are attempting to oust ISIS from Ramadi and Fallujah in the western part of the country. The pair of cities were a key battleground for U.S. troops in the most recent Iraq war, but the absence of American soldiers has threatened the turn country back over to the militants. On Friday, ISIS militants declared the region to be an Islamic state. The Washington Post spoke to a journalist familiar with the mood in Fallujah on Friday: 

"At the moment, there is no presence of the Iraqi state in Fallujah,” said a local journalist who asked not to be named because he fears for his safety. “The police and the army have abandoned the city, al-Qaeda has taken down all the Iraqi flags and burned them, and it has raised its own flag on all the buildings.”

Fighting broke out in the region earlier this week, after the Shi'ite-dominated government of Prime Minister Nuri Kamal al-Maliki cleared protest camps in the two cities. Some of the largely Sunni residents of Fallujah and Ramadi have been protesting for over a year over what they see as unfair treatment under al-Maliki's government. The government decided to remove its military presence from the cities on Tuesday — apparently in an effort to return calm. But al Qaeda militants almost immediately entered the region once the military withdrew. The military returned the next day, prompting the latest round of violence.