US President Barack Obama says the military jail at Guantanamo Bay is damaging US interests and he's vowed a renewed push to close it.

It comes as around 100 prisoners out of the 166 detained at the camp take part in a hunger strike.

He condemned the prison as a legal "no man's land and said he must continue to persuade Congress that the facility needs go.

At a White House news conference Obama told that it was time Congress agreed to shut the jail:

His comments follow the arrival of medical reinforcements yesterday to help deal with the hunger striking prisoners.

Obama first vowed to close Guantanamo Bay during his 2008 Presidential election campaign.