U.S. authorities are vowing to continue their month-long crackdown on illegal immigration in Los Angeles, after roughly 100 federal agents amassed near MacArthur Park in the Westlake area, but left without appearing to make any arrests.

The activity began shortly before 11 a.m. Monday, with dozens of vans and some military vehicles appearing out the outskirts of the park. An estimated 100 or more federal agents, many wearing vests identifying them as with U.S. Customs and Border Protection, appeared to be staging outside the park. About a dozen Border agents were also seen riding horses into the park.

As the federal presence grew and gained attention from local media and activists, protesters quickly moved into the area. Also showing up was Los Angeles Mayor Karen Bass, who was seen walking through the staging area, at one point speaking on a cell phone handed to her by a CBP officer.

Bass, who has repeatedly called for an end to federal immigration raids in the city, told reporters she had spoken on the phone to someone from CBP.

Asked for her reaction to the federal activity, Bass said, “They need to leave and they need to leave right now. They need to leave because this is unacceptable.”

Bass was then driven away from the area. A short time later, the federal agents all appeared to leave the area. Many of the protesters lingered near the park.

According to Fox News, the CBP official Bass spoke with on the phone was Chief Gregory Bovino of the agency’s El Centro Sector. Bovino told Fox News, “I don’t work for Karen Bass. Better get used to us now, cause this is going to be normal very soon. We will go anywhere, anytime we want in Los Angeles.”

Speaking at a news conference Monday afternoon, Bass called the MacArthur Park activity a continuation of a “political agenda of provoking fear and terror,” with federal agencies parading “armed vehicles in our parks when nothing is going on in our parks.”

Bass said a children’s summer camp was at the park Monday morning when the operation was conducted. The mayor also posted a video on social media showing federal troops, some on horseback, marching in formation through the park. She said it “looked like a city under siege under armed occupation.”

The activity was the latest event to raise the ire of local activists opposed to the immigration raids, which have stepped up over the past month.

Over the weekend, activists denounced what they called the continued presence of Immigration Customs Enforcement agents and contractors in the lobby of Dignity Health Glendale Memorial Hospital, where a woman was recovering after suffering a medical emergency while being detained.

They identified the woman as Milagro Solis Portillo and said she was injured Thursday during an immigration enforcement operation outside a Sherman Oaks apartment complex.

Activists said in a statement the presence of ICE agents was “creating a hostile and frightening environment for her, other patients, and hospital staff. Their presence is invasive and inappropriate in a medical setting. Milagro Solis Portillo deserves to heal in safety and dignity, free from intimidation and fear.”

ICE officials could not be reached for comment or to confirm their agents are waiting for the hospitalized woman.

It was also unclear why the woman was being detained or what caused her medical emergency.

The hospital Monday issued a statement saying, in part, “Dignity Health Glendale Memorial Hospital acknowledges the community’s concerns regarding Immigration and Customs Enforcement (ICE), and we share a desire to keep our neighbors safe. The hospital cannot legally restrict law enforcement or security personnel from being present in public areas which include the hospital lobby/waiting area.”

In Alhambra, activists pressed City Council members to be more proactive in combating ICE actions in their community, speaking in support of a resolution similar one adopted in June by Huntington Park’s elected officials, which authorizes local law enforcement to seek verification from people acting as immigration enforcement agents.

The council heard public comment and debated the issue for a total of three hours, and though most members voiced strong support for the spirit of the resolution, the panel ultimately decided to put off any action while staff worked to refine any potential legal issues.

Under the proposed resolution, Alhambra police would be required to:

— confirm the identity and legitimacy of individuals claiming to act as federal agents;

— enforce local laws and statutes accordingly, including the state law against vehicles having tinted windows, and issue citations to agents if they break the law;

— verify warrants and take note of the scope, dates, person mentioned in the warrant and the signing judge;

— restrict unjust unconstitutional searches, seizures and arrests if activities occur without a warrant.

Meanwhile, Homeland Security officials continued to encourage people in the country without legal standing to self-deport using the U.S. Customs and Border Protection Home App, which allows eligible individuals to notify CBP of their intent to depart the country, potentially avoiding detention and removal actions. Eligible people could receive travel assistance and a $1,000 “exit bonus.”

“We encourage every person here illegally to take advantage of this offer and reserve the chance to come back to the U.S. the right legal way to live the American dream. If not, you will be arrested and deported without a chance to return,” the department said.