Sana'a - Yemen on Sunday began enforcing a temporary ban on motorbikes in the capital to prevent "shoot and scoot" attacks in the city during national dialogue sessions.
The interior ministry said the ban will last until 15 December to "preserve security and stability" as Yemen undergoes a difficult political transition.
An AFP correspondent reported that the ban was being strictly enforced, with no motorcycles on the streets on Sunday.
Motorbikes are a cheap form of transport frequently used as taxis in the impoverished Arabian Peninsula country.
But they have also become a tool used for hit-and-run shootings that have killed dozens of officials nationwide.
Al-Qaeda in the Arabian Peninsula (Aqap) has been blamed for most of the motorbike attacks on members of the security forces.
The latest motorbike murder was on Tuesday when two gunmen on a bike killed a Belarussian defence contractor and wounded another as they left a Sana'a hotel.
On 22 November, Abdel Karim Jadban, a parliamentarian representing Zaidi Shi'ite rebels who fought a decade-long insurgency in Yemen's far north, was shot dead in a similar attack.
Hundreds of demonstrators protested on Saturday against the ban near President Abdrabuh Mansur Hadi's residence, where they were dispersed with water cannons and tear gas.
A security official in the capital, Colonel Yehya al-Akouaa, told AFP the ban aims to "prevent further attacks amid fears of an upsurge in such attacks as the national dialogue nears its end".
Yemen is experiencing a tough political transition since veteran president Ali Abdullah Saleh was ousted in February 2012 after a year of deadly protests against his 33-year rule.
The transition is expected to culminate in a new constitution and pave the way for parliamentary and presidential elections slated for February 2014, but it faces many hurdles.
There are growing demands for the secession of the formerly independent south, in addition to on-off fighting in the far north between the Shiite rebels and hardline Sunnis.
Yemen is also battling Aqap, which Washington regards as the jihadist network's most dangerous branch.
Aqap often attacks members of the security forces, despite a major army offensive last year and repeated US drone strikes targeting its commanders.