By BBC News Online's Russell Smith

For several weeks now President Omar al-Bashir has been involved in mounting rivalry with the influential speaker of parliament, Hassan al-Turabi, who has gradually been assuming power at the president's expense.

President Bashir's declaration of a state of emergency and dissolving of parliament is a clear raising of the stakes in his battle for political supremacy.

The move came just in time for President Bashir, as parliament pushed on by Mr Turabi, was due to vote on curbing his presidential powers less than 48 hours later.

Some analysts are already suggesting that the president's dramatic move could be a decisive turning point in his political fortunes.

Since September, when Mr Turabi outmanoeuvred him to be named secretary-general of the ruling National Congress party, the president's position had been looking increasingly vulnerable.

Former mentor

Mr Turabi, President Bashir's mentor and the main Islamic ideologue behind the radical Sudan Government, was a key ally when army General Bashir came to power following a coup in 1989.

Since then the Sudan Government has been a strategic alliance between the military and Islamic factions the leaders represent.

But the increasingly public rivalry between the two men came to a head in November with an open confrontation between them over moves to reduce presidential powers.

Their public row also coincided with significant progress made by President Bashir in recent months in seeking to end the 16-year civil war that has divided the nation. The two men are known to differ in their approach to the conflict.

If, as some opposition leaders suggest, the army holds the key to power in Sudan, then President Bashir should be in a strong position.

Followers of Mr Turabi are known to be already trying to gather signatures to force a reversal of the state of emergency.

Khartoum residents will be watching anxiously to see how the power struggle plays itself out.

With a divided government and an ongoing bitter civil war, political stability looks a long way off.