US President Obama is drawing scathing criticism for his failure to condemn the killing of nine Christians who were mercilessly gunned down by a mentally disturbed white assailant who barged into Umpqua Community College in Roseburg, Oregon, on Thursday morning and started shooting.

In his first reaction on the incident at a press conference at the White House on Thursday night, Obama conspicuously never mentioned anything about the Christian victims or called for religious tolerance, according to Fox News.

Indeed, in his statement, the president made it a point to mention that he was politicising the incident as he again made a case for gun control in America.

In his commentary on Fox News, Erick Erickson said, "What is so outrageous is that ... the president decided to politicise the situation after we already knew that the shooter had demanded the victims declare their religion before gunning them down. But the president never mentioned that. He never mentioned religious tolerance."

Erickson noted though that Obama did not politicise the killing of a TV reporter and her cameraman by a black gay man in Virginia last August. He also did not politicise the shooting last July in Chattanooga, Tennessee, where a Muslim radical killed six US servicemen.

Moreover, Obama did not politicise the shooting of a Muslim family in North Carolina last February when it turned out the shooter was a gay-rights supporting atheist, Erickson said.

Although Obama warmly greeted the visiting Pope Francis last week, his administration and its allies in all branches of government continue to harass Christians, the Fox News commentator said.

Erickson suggested that before Obama politicised the death of nine Christians in Roseburg, Oregon, he should have first asked himself: "Why are there more mass shootings under my watch than under George W. Bush's watch?"

"Evil is on the rise. It is real. It is active. It is global. And the president more often than not coddles it instead of confronting it," Erickson said.