New Delhi, April 30 -- The white supremacist who shot and killed 51 Muslims at two mosques in Christchurch, New Zealand, lost an attempt to undo his guilty pleas in a Court of Appeal ruling Thursday.

The panel of three judges dismissed Brenton Tarrant's claim that harsh prison conditions prompted him to make an involuntarily admission to terrorism, murder and attempted murder charges. His bid to withdraw his guilty pleas and seek a trial was "utterly devoid of merit," they wrote.

The Australian man, who is now 35, killed 51 worshippers and injured dozens more in March 2019 when he drove to two Christchurch mosques and opened fire with semiautomatic weapons during Friday prayers. Tarrant's guilty pleas in March 2020 brought relief to ber...