Hundreds of Comcast employees in Philadelphia streamed out of the Comcast Center on Thursday afternoon to protest President Trump's recent executive order barring refugees and immigrants from seven Muslim-majority nations.

The company put the crowd at 500 to 600, citing police estimates. Smaller protests were also held Thursday in Washington and Sunnyvale, Calif., according to the company and Twitter.

Under police escort at 2 p.m., Comcast employees walked south on 17th Street toward Market to reach Dilworth Plaza. The police closed off Market Street for the orderly procession. Comcast employees carried signs saying "Immigration Innovation" and "Tech Has No Borders." ​

They also chanted: "Love, not hate, will make our country great."

The 30-minute protest comes at a ticklish time for Comcast, which has long had a checkered relationship with the new president. In a recent conference call with Wall Street analysts, Comcast CEO Brian Roberts said the company looked forward to working with the Trump administration. Observers view the Trump-appointed officials as friendlier toward big mergers, which could benefit Comcast.

At the same time, the Comcast-owned NBCUniversal news and entertainment giant fell out with Trump, a one-time reality-TV star NBC helped create and then dumped. The top NBC entertainment executive called the Trump "toxic" and "pompous" in a private Facebook post that was made public last summer during the presidential campaign, and actor Alec Baldwin has ruthlessly satirized Trump on NBC's Saturday Night Live.

Trump believes that NBC and other mainstream outlets failed to treat him fairly during the election campaign. He also has taken to Twitter to bash Baldwin's SNL skits as "one-sided" and label NBC News "terrible."

On Monday, Google employees staged a protest over Trump's executive order  restricting Muslim immigrants.

The Comcast protest in Philadelphia developed over the last two days as employees in Silicon Valley communicated with headquarters employees internally over the messaging platform Slack, said Hai Thai, a Comcast employee and one of the Philadelphia organizers. The group also used twitter hashtags such as #techhasnowalls and #include.

Thai, 38, an immigrant from Vietnam, and Aaron Martin-Colby, 35, a Comcast software engineer who called himself "a very white guy," led the protesters.

"This is absolutely employee-organized and initiated," Martin-Colby said, adding that it had met "no resistance" from Comcast higher-ups.

A high-ranking executive showing his support for the event was Sree Kotay, the chief technology officer in the cable division. He did not speak to the crowd.

At Dilworth Plaza, Thai said to the gathered hundreds: "Wow. This is amazing." He said that in his "12 years at Comcast I have never felt happier than today."

One man passing through the plaza said "Go Trump."

Other Comcast employees spoke through small bullhorns at the plaza, recalling ancestors who had immigrated to the U.S. and how that diversity has made the country great.

Comcast spokesman John Demming said  Thursday that the company would pay employees for their time at the protest — as it would pay an employee for going to the doctor — and would treat Trump supporters the same way.