The pictures caused immediate outrage.
The United States said their publication contravened Hussein's rights as a prisoner and could have broken the Geneva Convention.
It has launched an investigation to find out who took the photos, and the military says it will question troops responsible for Hussein.
"The president [George W. Bush], has been briefed on the situation regarding these photographs," White House spokesman Trent Duffy said. "He strongly supports the aggressive and thorough investigation that's already under way. The source of these photos is unknown at this time, these photos were wrong, they are in clear violation of [Department of Defense] directives and possibly Geneva Convention guidelines for the treatment of detained individuals."
The paper, Britain's best selling daily, is unrepentant.
Today, "The Sun" published fresh pictures of Hussein in captivity.
And it made fun of the U.S. criticism: "Bush probes Saddam's Pants," runs today's headline. "Bush vows: 'I will get to the bottom of it.'"
But for Hussein's lawyers, it is no joke.
Ziad al-Khasawneh, who heads Hussein's legal team, said he plans to sue the paper and anyone who helped publish the pictures.
And he made parallels with notorious pictures from another Iraqi jail -- those of U.S. soldiers abusing Iraqi detainees at Abu Ghurayb prison.
"I was shocked when I was looking through the Internet at what was published by the British newspaper 'The Sun,' especially at what it published on its front page in addition to the inner pages," al-Khasawneh said. "In our opinion, this is a violation of all international agreements and human dignity, therefore we must sue the people responsible and the providers of these pictures; because if you look closely you can see that they were taken from his prison cell. This is considered as another Abu Ghurayb, and we will take the necessary legal actions which we have already started."
Hussein was captured in December 2003 and is being held by U.S. troops at an undisclosed location in Iraq as he awaits trial on numerous charges.
Aside from U.S. soldiers, the only others with access to the former Iraqi leader are his legal team, a prosecuting judge, and the International Committee for the Red Cross.
(compiled from news agency reports)