British Prime Minister David Cameron on Wednesday welcomed the "tough" punishment meted out to rioters by the courts as controversy erupted over lengthy prison terms for two men convicted of trying to incite a riot on Facebook.
"It's up to the courts to make decisions about sentencing. But they've decided to send a tough message, and it's very good that the courts feel able to do that," Cameron said.
Courts across England have held round-the-clock sittings to deal with the approximately 1,300 cases brought before them since the unprecedented wave of rioting, arson and looting in London and other cities last week.
Nearly 2,800 people have been arrested so far. In London alone, about 1,000 people have been charged in connection with the riots.
Jordan Blackshaw, 20, and Perry Sutcliffe-Keenan, 22, were each sentenced to four years by Chester Crown Court for trying to incite a riot on Facebook, although the events they attempted to organize did not actually take place.
The sentences were the longest handed out so far in the hundreds of speedy court convictions.
Both men pleaded guilty to "intentionally encouraging another to assist the commission of an indictable offence" under sections of the Serious Crime Act 2007, the Crown Prosecution Service said.
The judge said that, even though the men's call for violence and rioting was not taken up, the sentences were meant to act as a "deterrent" in the wake of the riots.
A spokesman for the prosecuting agency, the CPS, said the posts had caused "significant panic and revulsion in local communities as rumors of anticipated violence spread."
However, civil rights and penal reform groups have criticized some of the sentences handed down as "disproportionate" and blamed politicians for creating a "hysterical atmosphere" in their desire to see the rioters brought to justice.
Blackshaw used the social networking site to create an event -- with a date, time and location -- for "massive Northwich lootin.' "
Sutcliffe created a page on Facebook called "Warrington Riots" which listed a time and date for anyone who wished to be involved in a riot.
A lawyer representing Blackshaw said his client is remorseful and that his family is "shocked and upset" by the length of the sentence.
Cameron has said that everyone convicted in connection with the rioting should go to prison. His deputy, Liberal leader Nick Clegg, has suggested a "riot payback scheme" under which looters, wearing orange suits, would be forced to help clean up areas hit by the disturbances.
The Associated Press contributed to this report.