(CNN) -- American-born al Qaeda spokesman Adam Gadahn appears in a new video purportedly from the organization, calling President Obama "snakelike" and saying he is "running the affairs of a declining and besieged empire."
In the video, posted Sunday on Islamist websites, Gadahn criticizes what he says is the United States' "aggression and interference" in Afghanistan, Pakistan, Yemen and Somalia, and also criticizes moving his "captive brothers" from detention centers worldwide to "Muslim-only concentration camps in Illinois, Bagram [Airfield, Afghanistan] and elsewhere -- all in the name of protecting the American people from the threat of Muslim retaliation for American crimes."
He is apparently referring to a maximum-security prison in Thomson, Illinois, being considered by the government as a possible venue to house terror suspects.
CNN could not independently verify the authenticity of the 24-minute video, posted on websites known to carry such messages in the past and carrying the name of as-Sahab, al Qaeda's media arm. In it, Gadahn speaks in English; the video features Arabic subtitles.
"Yes, Barack," Gadahn says. "Just as our demands remain the same, the choice America and its allies face also remains the same -- either the possible restoration of your safety and security by ignoring the opposition of your tyrannical corporations and special-interest groups and restoring the rights you have stolen from Muslims and other persecuted and oppressed nations, or guaranteeing for yourselves a future of misery, insecurity and ultimately defeat, should you continue to ravage our countries, interfere in our affairs and trample on our dignity, liberty and sovereignty."
The solution to U.S. security, he says, does not lie in improving intelligence-sharing, "occupation" or supporting "despicable regimes."
Addressing Obama, Gadahn says, "I know that as you slither snakelike into the second year of your reign as a purported president of change, you are fighting, your hands full, with running the affairs of a declining and besieged empire, and in the process proving yourself to be nothing more than another treacherous, bloodthirsty and narrow-minded American war president."
In March, reports of Gadahn's arrest came hours after websites posted a video of him praising the November massacre at Fort Hood, Texas, saying suspect Maj. Nidal Hasan "lit a path" for other Muslim service members to follow. Two senior Pakistani government officials said investigators had arrested Gadahn, but later backed away from those reports.
The U.S. government has offered a $1 million reward for information leading to the capture of Gadahn, the first American charged with treason since 1952.
CNN's Amir Ahmed contributed to this report.