Zambian authorities closed the country's top courts on ​Monday, blocking access to the premises on the last day that ‌the opposition could file a challenge to this month's disputed election.

A memorandum from the chief administrator of the judiciary, which Reuters saw, said that "for security reasons, all members of ​staff are advised not to report for work today".

Police spokesman Godfrey ​Chilabi told Reuters that security assessments were ongoing and declined to ⁠give details. A spokesperson for the judiciary could not be reached.

Opposition leader Brian ​Mundubile said last week that he was planning to file a petition at the ​Constitutional Court to challenge the results of an August 13 election in which he came second to President Hakainde Hichilema.

The deadline to file such a challenge is seven days after the result was ​announced, which would be in the early hours of Tuesday.

OPPOSITION STILL AIMING TO ​FILE PETITION

At the Supreme Court premises in Lusaka, which also includes the Constitutional Court, all ‌of the ⁠gates were closed and police could be seen inside.

Hichilema won re-election with about 60% of the vote in the Southern African copper producer, but two reports by independent observers found indications that Hichilema's vote count was inflated. Hichilema has denied any ​fraud.

Following the arrests of ​several of his ⁠associates, Mundubile was summoned by police for questioning last week in connection with alleged national security threats, which he says are ​fabricated.

Analysts and human rights lawyers said they suspected he might ​be prevented ⁠from filing his petition, though Hichilema's party said that Mundubile was free to use the legal routes available to him.

"We are trying our best to ensure that the ⁠petition ​is filed, but we will see how it ​goes," said New Heritage Party President Chishala Kateka, whose party belongs to Mundubile's opposition alliance.