(CNN) -- President Barack Obama spoke with Egypt's president moments after Hosni Mubarak addressed his country, telling the Egyptian that he must make good on his promises and avoid a violent response to the thousands of protesters in the streets. With parts of his capital ablaze, Mubarak said he was asking his government to resign and would soon announce a new one, pledging to address the concerns of thousand of Egyptians protesting in Cairo's streets. "I just spoke to him after his speech," Obama said, "and told him he has a responsibility to give meaning to those words, to take concrete steps and actions that deliver on that promise. Violence will not address the grievances of the Egyptian people. Suppressing ideas never succeeds in making them go away.
@highlight
NEW: Obama calls Mubarak and tells him to openly address his people's grievances
@highlight
Privately, officials worry that Mubarak may be underestimating the protests
@highlight
Mubarak asks the government to resign
@highlight
Gibbs said the U.S. will review its "assistance posture" to Egypt
@placeholder, they said, has two choices: to embrace meaningful reforms or to continue the crackdown.