RIYADH: Saudi border guards arrested more than 19,000 infiltrators from troubled Yemen in June, nearly double the number caught the month before, a spokesman said Wednesday.

The sharp increase comes as Yemen's security situation is rapidly unraveling. Yemen's president is being challenged by a five-month-old popular uprising that has emboldened al-Qaeda-linked militants in the south of the country.

Yemenis routinely try to sneak into Saudi Arabia, its wealthy northern neighbor, in search of jobs. Saudi border guards usually send them back, though smugglers among the infiltrators are put on trial.

Saudi border guards have clashed several times with al-Qaeda militants crossing the border between Yemen and Saudi Arabia's southern Jazan border region.

Col. Abdullah bin Mahfouz, spokesman for Saudi's border command, said Wednesday that 19,145 infiltrators and 433 smugglers were arrested in June, virtually all from Yemen. Guards confiscated dozens of weapons, along with ammunition and drugs, the spokesman said.

In May, just over 10,000 infiltrators were caught, according to government figures.Last year, some 180,000 Yemenis were caught trying to sneak into Saudi Arabia.

Yemen, the Arab world's poorest country, has a population of nearly 24 million.