NEW YORK -- A protest against U.S. immigration policy forced the evacuation of the Statue of Liberty on the Fourth of July, with a group unfurling a banner from the pedestal and a woman holding police at bay for hours after she climbed the base and sat by the statue's robes.

The woman and at least a half-dozen demonstrators who displayed the banner were arrested, while the climb forced thousands of visitors to leave the iconic American symbol on the nation's birthday.

About 100 feet (30 metres) aboveground, the woman engaged in a four-hour standoff with police before two officers climbed up to the base and went over to her. With the dramatic scene unfolding on live television, she and the officers edged carefully around the statue toward a ladder, and she climbed down about 25 feet (8 metres) to the monument's observation point and was taken into custody.

The woman, Therese Okoumou, told police she was protesting the separation of immigrant children from parents who cross the U.S.-Mexico border illegally, according to a federal official who was briefed on what happened but wasn't authorized to discuss it and spoke on the condition of anonymity. A message left at a possible phone number for Okoumou wasn't immediately returned.

The climber was among about 40 demonstrators who earlier unfurled a banner calling for abolishing the federal government's chief immigration enforcement agency, said Jay W. Walker, an organizer with Rise and Resist, which arranged the demonstration.

Walker said the other demonstrators had no idea the woman would make the ascent, which wasn't part of the planned protest.

"We don't know whether she had this planned before she ever got to Liberty Island or whether it was a spur-of-the-moment decision," Walker said.

Regardless, he said he felt the publicity would help the group's cause.

A spokesman for the National Park Service, which runs the monument, saw it differently.

"I feel really sorry for those visitors today" who had to leave or couldn't come, spokesman Jerry Willis said. "People have the right to speak out. I don't think they have the right to co-opt the Statue of Liberty to do it."

The climber ascended from the observation point, Willis said. Visitors were forced to leave Liberty Island hours before its normal 6:15 p.m. closing time, he said.

Earlier and farther below, at least six people were taken into custody after unfurling a banner that read "Abolish I.C.E.," referring to U.S. Immigration and Customs Enforcement, whose officers arrest and deport immigrants who are in the U.S. illegally, among other duties.

Willis said federal regulations prohibit hanging banners from the monument.

Rise and Resist opposes President Donald Trump's administration and advocates ending deportations and family separations at the border.

U.S. Attorney General Jeff Sessions has said the president's immigration policy is a step forward for public safety.

Under Trump's zero-tolerance policy, the government has begun requiring border agents to arrest and prosecute anyone caught entering the country illegally. That resulted in more than 2,000 children being separated from their parents within six weeks this spring.

Under public pressure, Trump later halted his policy of taking children from their detained parents. A federal judge in California ordered the Trump administration late last month to reunite the more than 2,000 children with their parents in 30 days.

"Abolish ICE" has become a rallying cry at protests around the country and for some Democratic officeholders seeking to boost their progressive credentials. But Trump, a Republican, said on Twitter last week that abolishing ICE will "never happen!"

The Statue of Liberty has long been a welcoming symbol for immigrants and refugees coming to the U.S. It also has been a setting for protests and other actions that forced evacuations.

Last February, someone hung a banner reading "Refugees Welcome" from the observation deck. The sign was taken down about an hour after being discovered.

A year earlier, a West Virginia man was sentenced to time served after calling in a bomb threat that forced the evacuation of Liberty Island, sending 3,200 people on boats back to lower Manhattan and New Jersey.

In 2000, 12 people protesting the Navy's use of the Puerto Rican Island of Vieques for bombing exercises were arrested after a man climbed out on the spires of the statue's crown and attached flags and banners to it.

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Associated Press writer Michael Balsamo contributed from Los Angeles.