"We call upon the Iranian government to abide by the international obligations that it has to respect the rights of its own people," the president continued, pressing for the "immediate release" of those detained as a result of the protests.
"We will continue to bear witness to the extraordinary events that are taking place there," he added.
Obama's brief remarks on Iran -- delivered Monday afternoon at the end of his speech on the attempted bombing of Flight 253 -- arrive as protests in the Middle Eastern country are reaching a new intensity.
So far, eight been killed in the countless clashes between dissidents, who believe Mir Hossein Mousavi should be president, and government forces, acting under orders of President Mahmoud Ahmadinejad and his state's religious leadership.
Among those killed during Sunday's firefight was Mousavi's close nephew. The news of his death quickly galvanized the opposition movement, which continued its protests long into Monday.
In the United States, however, the White House has remained somewhat neutral since the disputed election in June. While the administration remains critical of Ahmadinejad's leadership, Obama has not publicly signaled support for Mousavi, in particular -- a move that angered some Republican lawmakers, who feel the White House has largely ignored an important political crisis in the Middle East.
Obama on Monday continued that approach, mentioning neither Mousavi's forces nor the death of his nephew that has recently catalyzed violence. But the president did acknowledge the power of the protesters and object to the Iranian government's harsh treatment of them.
"I am confident history will be on the side of those who seek justice," he said.