In a bid to end weeks of crisis after he postponed the February 25 presidential vote, Sall proposed a bill granting amnesty for acts committed in connection with political demonstrations since 2021.
The law, adopted by MPs last week, is expected to be published imminently but there is no official information when this might be.
Imprisoned anti-establishment candidate, Bassirou Diomaye Faye, and his coalition's detained firebrand leader, Ousmane Sonko, could be the main potential beneficiaries.
Unconfirmed rumors about their release have swirled, but it's unclear whether they would fall within the scope of the law.
Such a move will dramatically alter the presidential campaign, with Sonko's powerful rhetoric striking a chord with young voters.
Faye, who is one of the main contenders for the presidency, has been unable to address voters in person since campaigning kicked off on March 9.
Sall asked his government "to proceed without delay with the application of the amnesty law as soon as it is promulgated," according to a cabinet statement published late Wednesday.
Sonko was at the heart of a bitter two-year stand-off with the state and has been in prison since July.
The legal case against him, along with economic and social tensions, led to deadly unrest between 2021 and 2023.
The opposition figurehead came third in the 2019 presidential election but was disqualified from running in 2024.
Sonko then endorsed Faye, who has also been in prison since April 2023, to replace him on the ballot.
The "Diomaye President" coalition on Thursday organized a rally through the northern outskirts of the capital Dakar on the sixth day of the campaign trail.
Agitator or leader?
President Sall is not standing for re-election this year. His last-minute decision to defer the February presidential vote sparked clashes that left four dead.
A new date was finally set for March 24 after a month of political crisis.
Bouts of unrest since 2021 have killed dozens and led to hundreds of arrests in a country often viewed as a bastion of stability in coup-hit West Africa.
Sonko has been a divisive figure in the turmoil.
While some view him as an incendiary agitator, others see him as a leader of the people.
Sonko has always maintained there was a plot to keep him out of the 2024 election, while his camp and the government have traded blame for the violence.
The opposition figure was sentenced twice in 2023 -- for defaming a minister and for corrupting a minor.
He has been jailed since the end of July on a string of other charges, including provoking insurrection, conspiracy with terrorist groups and endangering state security.
His political party has also been dissolved.
Court hearings
Sonko's deputy, Faye, has been imprisoned since April charged with contempt of court, defamation and acts likely to compromise public peace after posting a message critical of the justice system.
Unlike Sonko, Faye has not been tried.
Sonko's eligibility to run in the election remains controversial.
Senegal's Supreme Court on Thursday was due to examine an appeal by the state against a court ruling which reinstated Sonko on the electoral roll.
After a brief hearing, the state withdrew the appeal and the case was closed, state lawyer Amadou Yeri Ba, told AFP.
Ba said the decision had no direct impact on Sonko's release.
On Friday, the Supreme Court is due to hear a request for the annulation of the presidential decree convening the electorate on March 24, brought forward by the party of disqualified candidate Karim Wade.
It is not yet known whether it is likely to succeed or what the consequences would be.
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