US President Barack Obama on Tuesday declared the United States and the entire world "appalled and outraged" by Iran's violent efforts to crush dissent, a clear toughening of his rhetoric as Republican critics at home pound him as being too passive. Obama condemned the "threats, beatings and imprisonments of the last few days." "I strongly condemn these unjust actions," Obama said in a news conference at the White House that lasted slightly less than an hour. Obama said his message has been consistent, and he shot back at Republican critics who are calling him timid: "Only I'm the president of the United States." When asked if his strong language on Tuesday was influenced by pressure from such Republicans as Sens. John McCain and Lindsey Graham, Obama scoffed: "What do you think?" In Teheran, chaotic images of riot police beating and shooting protesters have seized the world's attention and heightened pressure on Obama to act - or at least speak out more strongly. At least 17 people have been killed in protests since the election last week. The eighth extended question-and-answer session of Obama's presidency ranged from Iran to the intricacies of health care to a revealing personal moment in which Obama acknowledged he still is an occasional smoker despite his efforts to quit. In Iran, protesters have demanded that the government there cancel and rerun the elections that ended with a declaration of overwhelming victory for hardline President Mahmoud Ahmadinejad. Reformist presidential candidate Mir Hossein Mousavi says he won and has claimed widespread fraud. "I have made it clear that the United States respects the sovereignty of the Islamic Republic of Iran, and is not interfering in Iran's affairs," Obama said. "But we must also bear witness to the courage and dignity of the Iranian people, and to a remarkable opening within Iranian society. And we deplore violence against innocent civilians anywhere that it takes place." Obama noted the killing of a young woman, Neda Agha Soltan, whose apparent shooting death was captured on video and circulated worldwide. "We have seen courageous women stand up to brutality and threats, and we have experienced the searing image of a woman bleeding to death on the streets," Obama said. "While this loss is raw and painful, we also know this: Those who stand up for justice are always on the right side of history." Obama said he has watched the video. "It's heartbreaking," he said. "I think that anybody who sees it knows that there's something fundamentally unjust about it." Asked if Iran will face consequences for how it has acted, Obama said the world is watching and Iran's handling of dissent "will help shape the tone not only for Iran's future but also its relationship to other countries." Obama did not rule out shifting US strategy on Iran, which now calls for an opening of dialogue. "We are going to monitor and see how this plays itself out before we make any adjustments about how we proceed," the president said. Obama said the United States had provided a path for Iran to reach out to the international community and engage with global powers. "It is up to them to make a decision about whether they choose that path," Obama said. He added that the outlook "obviously is not encouraging in terms of the path that this regime may choose to take." Obama forcefully countered the idea that he's been slow to forcefully respond to Iran's violent crackdown on dissent. "I don't think that's accurate," Obama said. "Track what I've been saying." The president said he quickly responded after the election results and after violence broke out in the streets of Teheran, and that the United States has frequently condemned infringements on the freedom of assembly and speech for Iranians. "We've been entirely consistent," Obama said. On Sunday, Sen. Graham, a Republican, said: "The president of the United States is supposed to lead the free world, not follow it. He's been timid and passive more than I would like." McCain, a Republican who challenged Obama for the presidency, said: "I'd like to see the president be stronger than he has been. Earlier Tuesday, the US said that protests against the disputed Iranian presidential elections had begun to force change in the Islamic republic. "I think the world is watching. I think they [the protesters] have accomplished something. They've drawn attention to what's going on in Iran," White House spokesman Robert Gibbs told NBC. "I absolutely think we've seen the beginnings of change in Iran." Gibbs reiterated that the White House would not intervene in the internal turmoil in Iran, when asked whether US President Barack Obama would back an opposition-led general strike. "We're not going to get involved in endorsing or not endorsing specific actions inside of Iran," Gibbs said. "This is for Iranians to debate - their next leadership. I think the president wants to ensure that he doesn't become a political football that the regime uses against anybody that seeks justice in Iran." However, speaking to Fox News, Gibbs if there is a tremendous escalation in violence in Teheran, the White House would intervene. "Obviously if a tremendous escalation happens - if tanks happen - we would respond to that immediately," Gibbs said.