"Nominations for the presidency will be called for on July 19 and a vote will be taken on July 20 to elect a new president," the parliamentary speaker was quoted as saying by the Daily Mirror on Monday.
Abeywardena said that, under the constitution, the parliament will convene on Friday to be officially notified that the presidency is vacant. The next leader will head an all-party interim government until a new popular vote is held.
Earlier in the day, the Russian Foreign Ministry said that Moscow was awaiting the formation of a new government in Sri Lanka and was ready to cooperate with it.
"We proceed from the fact that the events in Sri Lanka are its internal affair. We hope that the further development of political processes in our friendly country will take place in accordance with its constitution and current laws," the ministry said in a statement.
The ministry stressed that they hope for a fast normalization of the situation and the adoption of necessary measures to overcome the crisis in the national economy by the new Sri Lankan authorities.
Meanwhile, the United Nations voiced support for a smooth transition of government in Sri Lanka and called on "all stakeholders" to engage in dialogue to achieve that goal.
"The Secretary-General condemns all acts of violence and calls for those responsible to be held accountable, underlining the paramount importance of maintaining the peace. The United Nations stands ready to support Sri Lanka and its people," spokesperson Stephane Dujarric said on Monday.
The island nation is suffering from the worst economic crisis in its independent history, with protesters blaming lack of food, cash and fuel on years of mismanagement by Rajapaksa and his family.