Kerry said Assad had not yet realized the inevitability of his ouster, adding that there were additional things that could be done to change Assad's current perception of the viability of his regime.
"We need to address the question of President Assad's calculation currently," Kerry said at a joint press briefing with his Jordanian counterpart, Nasser Judeh, at the State Department.
"I've got a good sense of what I think we might propose,” he said, but he did not divulge the exact nature of his proposal, saying, “we need to really consult with an awful lot of players here before we start again making any kind of public announcements.”
Kerry is expected to visit several European and Middle Eastern capitals, according to various news agency reports that cited diplomats. His itinerary was not yet to be announced officially, the reports said.
Jordan’s Foreign Minister Judeh said that “nobody can put a timeline” on Assad’s stay in power but added that there was a “conviction all around that it is a political solution that needs to kick in, and the current situation [of civil war] is untenable.”
King Abdullah of Jordan is planning to visit Russia in the near future to discuss issues concerning the Middle East, including Syria.
Russia has been insisting that Assad’s ouster should not be a precondition for negotiations between the rebels and the government.
Assad stressed on Monday that his government would not submit to pressure or “plots” against it, the state-run SANA news agency reported.
"Syria will remain the beating heart of the Arab world and will not give up its principles despite the intensifying pressure and diversifying plots not only targeting Syria, but all Arabs," Assad said at a meeting with a Jordanian delegation in Damascus, according to SANA.
The Syrian regime had earlier said it was open to dialogues with the opposition, but without preconditions.
Kerry’s comment on Syria came a day after President Barack Obama overlooked the Syria crisis in his State of the Union address.
Though Obama said he would keep up the pressure on the Syrian regime, his remarks were not as stern as they were in his address last year.
However, Kerry said the president’s Syria policy was “crystal clear.”
“The preference of the administration is to make sure we have a political solution, if at all possible,” Kerry said. “That is the preferable outcome here, that there be a negotiated solution.”
Referring to Assad’s departure, Kerry said “the president I think believes, I believe, that that is going to happen.”
“I’m not going to get into timeframes, but I am convinced that the current track on the ground is going to result, at some point in time -- and King Abdullah, in fact, earlier today confirmed to me it was his impression also, and I think it’s the impression of others, that there is an inevitability here,” he added.
The New York Times reported earlier this month that a plan developed last summer by then-Secretary of State Hillary Clinton, and the then-CIA Director David Petraeus to arm and train the Syrian rebels had been rejected by the White House over concerns that it could draw the U.S. into the Syrian conflict and the arms could fall into the wrong hands.