Appearing in army uniform for a news conference in the capital, Khartoum, Mr Bashir said Hassan el-Turabi, the speaker, had repeatedly tried to undermine him in recent weeks, leaving him with no option but to declare a three-month state of emergency. "Two captains leading one ship will cause it to drown," Mr Bashir said.
Earlier Mr Turabi denounced the state of emergency, introduced by the president two days before a parliamentary vote to limit his powers was due. "This was a plain and clear coup d'etat, despite the justification provided by Bashir," said Mr Turabi, an Islamist who is secretary-general of the ruling National Congress Party.
Mr Bashir, an army lieutenant-general, came to power in a military coup in 1989 sponsored by Mr Turabi and his now-defunct National Islamic Front. Even though Mr Bashir became president, Mr Turabi remained the regime's ideologue and strongman.
Yesterday, Mr Bashir, who dissolved parliament and suspended parts of the constitution, said Mr Turabi's attempts to undermine him had included setting up a committee last week, before which he had been expected to justify his absence from a National Congress meeting. Mr Bashir refused to appear before the committee.
Over the past year, a number of Mr Bashir's powers have been transferred to Mr Turabi, and more were expected to be handed over to him at the parliamentary session which was to have taken place today. Among the planned changes was a proposal to create a new prime minister's post and to amend the constitution to allow parliament to remove the president by a two-thirds majority.
But Mr Bashir said he had no immediate plans to try to contain Mr Turabi, who is supported by elements of the Sudanese defence forces.
Mr Bashir said he had acted within the constitution to unify Sudan in the face of outside threats, such as what he described as recent moves by the United States. The US last month approved a law allowing Sudanese rebels, who have been fighting the government for the past 16 years, to receive food aid.
President Bill Clinton has yet to decide whether to implement the measure, but the US has long accused Khartoum of supporting terrorism.