Saudi Arabia's king has called for the areas of Mecca and Medina to be modernized, in an effort to prevent future stampedes like the one Sunday that killed 244 people and injured hundreds more during the annual Muslim pilgrimage, the hajj. Saudi King Fahd bin Abdul Aziz issued the decree late Sunday, ordering a 20-year development project that would improve safety for the millions of Muslims who arrive for the pilgrimage each year.

The latest tragedy was caused by massive crowds during the stoning ritual on Sunday.

The ritual begins on the third day of the five-day hajj, as masses of pilgrims assemble near a series of pillars that represent the devil. Muslims believe that this is the site where Satan appeared to the biblical patriarch Abraham. Pilgrims are required to throw seven stones at the pillars in a symbolic rejection of evil.

The stoning ritual has resulted in hundreds of fatalities in recent years because as many as two million pilgrims are trying to get close to the pillars at once. The pressure of the human swell often causes people to slip and fall.

Sunday's death toll was the highest in a stampede since 1994, when 270 people died in the village of Mina under similar circumstances.

The worst pilgrimage tragedy in recent history was in 1990, when more than 1,400 people were trampled to death while trying to pass through a tunnel in Mecca.

Sunday's deaths occurred despite Saudi efforts to improve security and crowd control in advance of the event.