Unidentified militants from Yemen killed a Saudi border guard and injured another, according to Reuters. 
Around three in the morning, Sabq online news reported that Saudi guards "came under heavy fire" from the Yemeni side of the border in the eastern part of Jizan province.  According to Jazan Today, the border guards were exchanging fire with smugglers. Monday's violence was preceded by similar attacks last Thursday in Asir that left another two border guards dead.  Saudi Arabia considers its "porous" border with Yemen as a "serious security threat,"  in part due to smuggling, but also due to the fact that many Al Qaeda recruits use the border to enter Yemen where one of the strongest Al Qaeda chapters is located.