Nigeria's political parties must select their candidates for the country's 2019 presidential election between Aug. 18 and Oct. 7 this year, the electoral commission said on Tuesday in a timetable of the polling process.

Presidential and parliamentary elections will be held on Feb. 16, 2019, marking the end of President Muhammadu Buhari's first term. Buhari has not said if he will seek re-election.

In addition to outlining the deadline to select candidates, the timetable published by the Independent National Electoral Commission (INEC) stated that official campaigns for the presidential parliamentary elections would begin on Nov. 18.

"The Commission wishes to assure Nigerians that we are determined to strictly adhere to the timetable and schedule of activities," INEC said in a statement.

Buhari, 75, took office in May 2015 after winning elections that year following a campaign in which he vowed to crack down on endemic corruption and crush the Boko Haram Islamist insurgency in the northeast.

Although the president has not said whether he will run in the next election, the minister of communications last week said he would chair a group to support the re-election of Buhari and Vice President Yemi Osinbajo.

It is common practice for the campaign to re-elect a Nigerian president to begin with such support groups before the incumbent declares an intention to run again.

Atiku Abubakar, a former vice president and key Buhari ally, quit the ruling All Progressives Congress and said he was prepared to run in 2019. He joined the opposition People's Democratic Party last month.