WASHINGTON — Police on Monday arrested activists who unfurled a banner reading, "Tibet Will be Free," on a major Washington bridge during a closely watched visit by China's leader-in-waiting Xi Jinping.

Officers briefly took four people into custody after they rappelled down the Arlington Memorial Bridge, which connects Virginia with central Washington's National Mall, to hang the banner, police said.

The four -- two of whom were taken by a police boat as they dangled down the side of the bridge over the Potomac River -- were arrested on charges of trespassing, US Park Police spokesman Sergeant David Schlosser said.

The activists from the group Students for a Free Tibet said that they were later released after being issued citations with fines of about $250 each for trespassing and disorderly conduct.

"I wanted to send a message to Xi Jinping, and also to the Tibetan people that we stand in solidarity with them," said one of the four, Tenzin Jigme.

"To Xi Jinping and the Chinese government, we want to say that they cannot continue with this violent crackdown on peaceful Tibetans," he said.

At least 19 Tibetans have set fire to themselves in the past year to protest what they see as a lack of rights under Chinese rule, leading Beijing to impose virtual martial law, according to residents and exiled groups.

China has disputed the accounts and accused overseas groups and Tibet's exiled spiritual leader the Dalai Lama of fomenting unrest.

Flag-waving protesters also marched to the White House and planned further demonstrations on Tuesday when Xi meets with President Barack Obama.

"Xi Jinping is the last person that we believe President Obama should basically have a date with on Valentine's Day," activist Lhadon Tethong said.

"He represents everything counter to what Americans believe about human rights, freedom, democracy and dignity of people," she said.

Xi, who arrived Monday in Washington, is expected to become China's president in 2013 in a transition that starts later this year.