Tensions are rising between the Pittsburgh Post-Gazette and its striking workers.
A short video on the post-gazette's website appears to show part of the incident between a delivery driver and striking workers late Saturday at the company's newspaper depot on West Carson Street.
The paper says the video is from an independent security firm.
It appears to show workers verbally confronting the delivery driver, when one begins to move closer to the driver.
The driver appears to punch the worker, then gets into a fight with another.
The Newspaper Guild of Pittsburgh called the incident an assault on striking workers, adding it was unprovoked and one worker required surgery for a broken jaw.
In a statement, the paper said it's the latest in a string of altercations between striking workers and staff, which have allegedly included verbal assault, threats, and damage to property.
Workers have been on strike since October.