U.S. Secretary of State John Kerry said Tuesday that a political transition in Syria could take place within the next few months if the proposed ceasefire holds and all parties agree to come to the negotiating table. The statement in the Senate Foreign Relations Committee hearing was the first from the secretary that indicated a set timeline for a ceasefire and the potential ousting of Syrian President Bashar Assad.

"We are talking about months. If it is real and is really happening, [the negotiations] could move," Kerry said of the proposed ceasefire in Syria. "If it takes too long, there are people who could say this is a farce and will walk away." 

Kerry said in his testimony Tuesday that he is confident the negotiations on a political transition will go forward because the U.S., Iran and Russia are communicating more about the details of the plan.

"President Putin said and has said publicly that [Russia] is committed to this process," Kerry said, adding that the U.S. still wants Assad out of power as a condition to moving forward with the political transition. He said in the political talks on Syria there has been "no discussion" about charging Assad with committing war crimes.

SyriaBombing Damaged buses are seen at the site of two bomb blasts in the government-controlled city of Homs, Syria, in this handout picture provided by SANA on Feb. 21, 2016. Photo: REUTERS/SANA/Handout via Reuters

The Senate Foreign Relations Committee hearing Tuesday comes just one day after the U.S. and Russia proposed a plan to implement a ceasefire in Syria. 

The plan took its current shape after Kerry and Russian Foreign Minister Sergey Lavrov spoke on the phone Sunday, according to the State Department. It is unclear whether Kerry spoke to his counterpart in Iran, but State Department spokesman John Kirby said Monday that the Middle Eastern country had been contacted. It is unclear whether the Syrian opposition had been briefed on it.

The details in the ceasefire document are sparse and do not clearly define the scope of the plan. It is unclear whether or how Syria, the U.S., Russia and Iran would be able to continue their military operations in the country. The document does not describe who would monitor the ceasefire on the ground and which country or international body would be in charge of reporting ceasefire violations.