Updated

Yemen has asked the International Organization for Migration to help some 200,000 Yemenis forced to leave Saudi Arabia in the past three months amid a crackdown on undocumented migrants, the IOM said Friday.

Yemen wants the IOM to help provide basic assistance such as shelter, access to water and hygiene kits to vulnerable returnees, the Geneva-based organisation said in a statement.

Saudi King Abdullah announced an amnesty on April 3 that grants foreign workers a three-month grace period to regularise their residency or leave the country to avoid being jailed, fined or placed on a blacklist.

The oil powerhouse, which wants to reduce the number of foreign workers to address an unemployment crisis, earlier this week extended the time limit to November, and the IOM cautioned even more Yemeni migrants could flow out of the country in the coming months.

The group said some of the returnees were "thought to have been in Saudi Arabia for two or three generations."

Yemen also asked the IOM to allow returnees to use the organisation's existing medical and other facilities in the Saudi border town of Haradh, mainly used today for stranded migrants from the Horn of Africa region.

Some 84,000 people from Horn of Africa countries flooded into Yemen last year hoping to find jobs in Saudi Arabia and the Gulf countries, up from 34,000 in 2010, the organisation said.

Another 35,000 migrants from the region arrived in Yemen during the first five months of this year, it added.

The Saudi crackdown on undocumented migrants, the fencing of its border and Yemeni raids on people smugglers' camps have left many migrants stranded in Haradh, which currently is estimated to house some 25,000 irregular, destitute migrants, often in "terrible conditions, without adequate shelter and access to food, water and medical assistance", the IOM said.

According to official statistics, eight million expatriates work in Saudi Arabia, where there are reportedly around two million illegal workers.