Indian police personnel stand alert at the entrance to Central Jail in Nagpur where 1993 Mumbai blast convict Yakub Memon is detained.

AFP/New Delhi

India's top court on Wednesday rejected a last-ditch plea by a convicted bomb plotter, clearing the way for his execution.

Yakub Memon had petitioned the Supreme Court to halt his hanging, scheduled to take place on Thursday morning, on the basis that his death warrant had been issued before all legal avenues to appeal were exhausted.

He was convicted of plotting a series of coordinated bomb attacks in Mumbai in 1993 that killed 257 people, the deadliest attacks ever to hit the country.

"(The) death warrant is legal and there is no legal infirmity in it," the court said in its ruling.

The top court had on July 21 rejected a final appeal by the 52-year-old, who has spent more than two decades in jail.

Eleven people have been convicted over the 1993 attacks, which targeted the Mumbai Stock Exchange, the offices of Air India and a luxury hotel in India's commercial capital.

They were believed to have been staged by Mumbai's Muslim-dominated underworld in retaliation for anti-Muslim violence that killed more than 1,000 people.

Memon and two of his brothers were convicted in 2006 by a specially-designated court using controversial anti-terror legislation that was introduced after the 1993 bomb blasts and is no longer on the statute books.

Another brother, Tiger Memon, was alleged to have masterminded the attacks along with Mumbai gang boss Dawood Ibrahim.

Both have been on the run since 1993 and Yakub Memon is the only one of the 11 convicted to have had his death sentence upheld on appeal.

The only remaining barrier to his execution is a mercy petition he filed with President Pranab Mukherjee, who could stay the execution.

Last year Mukherjee rejected a similar plea filed by Memon's family.