The protesters said they wouldn’t leave until Wheeler meets with them over their demands that he resign, reduce the Portland Police Bureau budget and never vote to increase police spending.
The protest appeared to be peaceful as of 10 p.m. local time, although red-paint handprints were seen on the glass outside the lobby, according to independent journalist Garrison Davis.
Some of the protesters had left by 10 p.m. for unspecified "safety reasons," Davis reported.
Late Friday, Wheeler's office released a statement saying, "We are monitoring the situation and hope protesters remain peaceful for the safety of other residents," according to KION-TV reporter Jennifer Dowling.
It was not immediately clear if Wheeler was home during the protest.
Earlier, Wheeler tweeted a message, praising the protesters' efforts.
“Thank you Portlanders for a powerful display of solidarity at last night's demonstrations,” he tweeted. “Racial justice requires the entire community to come together. Let's continue to focus on the work ahead and move forward with reform, recovery and resilience plans for PDX.”
Earlier Friday, Wheeler wrote a letter to President Trump, declining an offer of more federal officers to quell rioting that has plagued the city since the May 25 death of George Floyd in police custody in Minneapolis.
“We don’t need your politics of division and demagoguery,” he wrote. “When you sent he Feds to Portland last month you made the situation far worse. Your offer to repeat that disaster is a cynical attempt to stoke fear and distract us from the real work of our city.”
Wheeler also condemned violence and vandalism that has marred mostly peaceful protests.
“There is no place for looting, arson or vandalism in our city,” he wrote. “There is no room here for racist violence or those who wish to bring their ideology of hate into our community. Those who commit criminal acts will be apprehended and prosecuted under the law."
The presence and tactics of federal agents who were sent to the city last month to protect the federal building downtown amid nightly protests were highly controversial. Agents have since been drawn down.
The local U.S. attorney announced Thursday that 74 people are now facing federal misdemeanor and felony charges related to protesting, include assaults on federal officers, arson and damaging federal property.
In a tweet a few hours later, Trump called Wheeler “incompetent” and said if he couldn’t get control of the city “we will go in and take care of matters the way they should have been taken care of 100 days ago!”
The Associated Press contributed to this report.