Sudan's President Omar al-Bashir is one of the Middle East’s longest ruling leaders and has crushed two previous bouts of protests in recent years. File picture: Burhan Ozbilici/AP

Cairo - Sudan's Omar al-Bashir fended off a march by opponents on his presidential palace in the capital, Khartoum, unleashing his security forces in hopes of putting an end to an Arab Spring-style uprising. But nearly a week of protests has pointed to the weaknesses threatening his 29-year hold on power.

Despite the heavy hand of police, who have reportedly killed at least 37 protesters, al-Bashir's response has been feeble. He left the capital ahead of Tuesday's march on his palace, and he has been fumbling and vague in addressing the economic crisis that prompted the outburst of anger.

Sudan's President Omar al-Bashir, centre, greets dignitaries as he arrives at the airport in Juba, South Sudan. File picture: Bullen Chol/AP

Perhaps most alarming for al-Bashir, an Islamist who came to power in a 1989 military coup, the powerful military and security agencies have only voiced half-hearted support for him amid the turmoil.