The Athletics Integrity Unit (AIU) confirmed it had given RusAF until January 2 to provide explanations for the "serious anti-doping breaches" by officials from the governing body, uncovered following a 15-month investigation.

RusAF had previously been set a deadline of December 12 to file its response to the AIU.

The scandal toppled former RusAF President Dmitry Shlyakhtin, replaced on an acting basis by Yulia Tarasenko, and prompted World Athletics to warn it was considering expelling the embattled organisation.

World Athletics also froze the reinstatement process for RusAF and put its system of allowing Russian athletes who meet strict criteria to compete as neutrals on hold.

Tarasenko claimed earlier this month that she still expects Russian track and field competitors to participate as neutrals at Tokyo 2020, despite a series of sanctions imposed on the country by the World Anti-Doping Agency (WADA).

WADA handed Russia a four-year ban after an investigation found data from the Moscow Laboratory had been tampered with before it was handed over to the global watchdog in January.

The sanctions from WADA mean Russia's flag will be banned from major events, including Tokyo 2020, while the country is also set to be stripped of World Championships it has been awarded. 

WADA ruled that Russian athletes who can prove they had no involvement in the doping scandal or the cover-up will be able to compete - a condition Tarasenko claims should apply to track and field competitors.

Shlyakhtin, appointed RusAF President in 2016, was suspended by the AIU for his involvement into whereabouts violations committed by Lysenko.

He has been accused of using fake medical documents in an attempt to ensure Lysenko avoided punishment and of failing to cooperate with an investigation.

A total of seven individuals associated with RusAF are among those charged by the AIU.