Saudi Arabia has arrested more than 4,000 people and seized large quantities of weapons and
drugs in the south of the country, along the border with Yemen.
Both Yemen and Saudi Arabia are combating Islamic militants believed to be linked to Saudi-born Osama bin Laden's al Qaeda.
The official Saudi Press Agency (SPA) said border police had seized dynamite and ammunition as well as hashish and wine with the 4,047 infiltrators. Saudi authorities have in the past reported on arrests and arms hauls in Najran.
Saudi Arabia has recently stepped up security along its border with Yemen, a traditional route for drug and arms smuggling. Yemeni and Saudi militants have also crossed the border.
At least 50 people have been killed in suicide car bombings in Saudi Arabia since May. Yemen is bin Laden's ancestral homeland and has also suffered attacks by al Qaeda sympathisers against national and foreign targets.