Tensions are escalating between demonstrators who wish to slow gentrification in parts of San Francisco and Oakland and the tech companies that shuttle thousands of high-paid Silicon Valley employees in private buses through the city. The New York Times reported that on Friday, protestors stopped three of these Silicon Valley shuttle buses – two run by Google and one run by Apple – during the rush-hour morning commute.

Google employees were on pins and needles when demonstrators smashed a window and slashed the tires of one of the commuter buses. The bus was ferrying Google employees through Oakland when it was stopped.

“Bus window smashed this morning in protest of Google eating The Bay & picking its teeth with the bones,” Twitter user @OccupyOakland tweeted on Friday, along with a photo of shattered glass in the street.

Demonstrators protesting the tech industry’s impact on San Francisco say the rising rent prices, spurred in part by an influx of young tech professionals who prefer the city to the suburbs around Silicon Valley, are causing evictions. According to USA Today, the median rent in San Francisco jumped 27 percent in the past two years, to $2,800 per month.

"We want the ruling class, which is becoming the tech class, to listen to our voices and listen to the voices of folks that are being displaced," said one San Francisco protester.

Protestors handed out fliers to employees riding the Google buses and the Apple bus that described demonstrators’ reasons for blocking the buses. One employee posted a photo of the flier to Twitter.

"While you guys live fat as hogs with your free 24/7 buffets, everyone else is scraping the bottom of their wallets, barely existing in this expensive world that you and your chums have helped create," the flier reads. “You are not innocent victims. Without you, the housing prices would not be rising and we would not be facing eviction and foreclosure. You, your employers, and the housing speculators are to blame for this new crisis, so much more awful than the last one.”

Some people were confused about why protestors chose to target tech employee shuttle buses, which take a number of cars off the road and contribute to better public transportation and less congestion.

“This protest targeted the wrong company,” wrote one commenter on indybay.org’s account of the Gbus incident. “Google is bringing money to the Bay Area; fighting Google isn’t going to fix poverty. And unlike many big companies, Google tends to spread the wealth around to its thousands of employees, who all end up spending more — yes, on rent as well, but also on goods and services.”

According to USA Today, nearly 40 companies now operate shuttle buses throughout the Bay Area. Google alone runs over 100 buses that make a total of 380 trips to the city a day. There have been several complaints that the buses clog public bus lanes. Still, many people demur with the protestors, saying that their actions against the buses and the employees who rely on them are objectionable.

"The vandalism and violence against employee shuttles and the workers who ride them is unfortunate and unacceptable," the Bay Area Council, a business group representing many of the shuttle bus operators, said in a statement.

Click through the slideshow above to see photos from Friday’s events.