(Bloomberg) -- MTN Group Ltd. shares fell almost 7 percent after Nigeria’s government said Africa’s biggest mobile operator evaded taxes and urged a Lagos court not to block a $2 billion penalty.

The High Court of Lagos should throw out the Johannesburg-based company’s attempt to stop it from paying backdated taxes, T. A. Gazali, a government lawyer, said in court Tuesday.

Wole Olanipekun, a lawyer for MTN, said Nigeria’s attorney-general, who imposed the penalty on the mobile carrier, had no right to do so. MTN has previously denied it didn’t pay taxes properly in the West African nation. The case was adjourned until May 7.

READ: MTN Plans Nigeria IPO Once $2 Billion Tax Case Is Resolved

MTN fell as much a 6.8 percent, the most in more than five months, before paring losses to 2.1 percent by noon in Johannesburg.

MTN’s share price has fallen 17 percent since it was hit by a double Nigerian penalty in mid-2018. The Central Bank of Nigeria first ordered it to transfer $8.1 billion of repatriated dividends back to the country, before the attorney-general announced the measure on taxes. The company settled the former dispute in December, agreeing to send back $53 million and clearing itself of any wrongdoing.

MTN plans to list its Nigerian unit, which has 58 million mobile-phone subscribers, in Lagos once the tax issue is resolved. It will be the biggest company on the bourse by revenue, having made sales of 1 trillion naira ($3 billion) last year.

(Updates from first paragraph with drop in shares.)

To contact the reporters on this story: Tope Alake in Lagos at talake@bloomberg.net;Paul Wallace in Lagos at pwallace25@bloomberg.net

To contact the editors responsible for this story: Antony Sguazzin at asguazzin@bloomberg.net, Sophie Mongalvy, John Viljoen

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