Milwaukee (AP): Democratic presidential candidate Barack Obama, following a campus shooting in his home state of Illinois that left six dead, said on Friday that the US must do "whatever it takes" to eradicate gun violence.

Obama stressed, however, he believes in an individual's constitutional right to bear arms.

Obama said he spoke to Northern Illinois University's president this morning by phone and offered whatever help his Senate office could provide in the investigation and improving campus security.

The first-term senator, a former constitutional law instructor, said some scholars argue the Second Amendment to the US Constitution guarantees gun ownership only to militias, but he believes it grants individual gun rights.

"I think there is an individual right to bear arms, but it's subject to commonsense regulation" like background checks, he told reporters while campaigning in neighbouring Wisconsin.