According to the Syrian Observatory for Human Rights, US and coalition airstrikes against the northern Syrian city of Manbij have killed at least 20 civilians today, bringing the death toll of the nearly two month siege to around 100 civilians.

The US-backed Syrian Democratic Forces (SDF), a Kurdish-dominated faction, has been trying to take Manbij since late May, and has entered the city a few times, though they’ve never gotten too far beyond the entrance as ISIS snipers quickly pin them down, and ISIS counterattacks have repeatedly pushed them back.

Manbij’s value is primarily its location along the Tigris River, where it links ISIS territory along the Turkish border in Aleppo to its de facto capital city of Raqqa. If the city and surrounding area fell, it would greatly weaken ISIS’ ability to move fighters between the two regions.

Some 50,000 civilians are believed to be in Manbij, which has made the repeated US airstrikes against the city extremely problematic. While the US rarely admits to any civilian deaths, this huge toll once again reflects why the US-backed forces aren’t being greeted as “liberators” when they take cities.