The hacker group Anonymous has taken down a US tourism website in Orlando, Florida as a protest against the arrests of people handing out food to the city's homeless.
Anonymous said the attack on orlandofloridaguide.com was retaliation for the arrest of members of the group Food not Bombs.
The website, which is not owned by the city, went offline for part of Tuesday.
Anonymous rose to prominence by hacking the sites of major corporations.
Anonymous is often seen as a political collective and has pledged to take action against those its members view as acting improperly.
They have been linked to several high-profile web attacks, including several on Sony websites as well as the Church of Scientology.
'Balance of needs'Anonymous has warned that more attacks could follow as part of what it has dubbed "Operation Orlando".
In a news release, the hacker group promised to carry out a distributed denial of service attack (DDoS) on a separate Orlando-related website every day until the arrests come to an end, choosing orlandofloridaguide.com as its first target.
The collective also said it will email millions of people across the world asking them to boycott the destination.
"This is a declaration of war," said Anonymous, describing Operation Orlando.
"Anonymous will now begin a massive campaign against you and your city web assets," it added in a message directed at Orlando officials.
But orlandofloridaguide.com, which went offline for several hours on Tuesday, has no affiliation to the city, an Orlando spokesperson told the BBC.
"I don't know what the hackers' intentions are, but from the city's standpoint, we're just trying to balance everyone's needs," the spokesperson said.
'Difficult position'The row between the city of Orlando and the non-profit organisation Food Not Bombs started when the group began feeding homeless people in a park in the city's downtown.
They did not obtain a permit to do so, a move which is required by law in Orlando.
Since then members of Food Not Bombs, including the group's president, Keith Mchenry, have been arrested several times in the past month for handing out meals.
"We're in a difficult position, and we've tried everything," the Orlando spokesperson said.
"If Food Not Bombs continues to violate the ordinance, they will be subject to the consequences of violating it, which is arrest."
Meanwhile, Food Not Bombs has said it has no affiliation with the Anonymous hacker group.
Spanish police arrested three suspected members of the Anonymous group earlier this month.