MANAMA - Yemen's security chief has told Iran to stop training and funding Shi'ite Muslim rebels who, along with al-Qaida-backed Islamists and southern separatists, are staging one of three insurgencies threatening to pull the chaotic country apart.Major-General Ali al-Ahmadi, president of Yemen's National Security Board, also said al-Qaida appeared not to number more than 700-800 in the country, including a few hundred Saudis.Saudis in al-Qaida Ahmadi also said the exact size of Yemen-based al-Qaida in the Arabian Peninsula (AQAP) was unknown."Al Qaeda seems to me to not exceed 700-800 elements, but there are also sleeper cells we don't know about. The majority are Yemenis," Ahmadi said. "The second group are Saudis, of which there are hundreds, but it is very hard to be precise." Islamist militants exploited protests last year against then-Yemeni President Ali Abdullah Saleh to seize several towns in the south before a U.S.-backed government offensive drove them out. T he y included many Saudis who had fled after the kingdom crushed a wave of attacks in 2006.Saudi officials have described AQAP as the kingdom's most serious security threat and have worked closely with Sanaa against the group.Security analysts in the Gulf say Saudis comprise much of the leadership of AQAP, but that a series of recent defections and assassinations may have weakened morale."Saudis bring ideology, funding and bomb-making expertise to AQAP," Ahmadi said. "More than 13 nationalities have come to Yemen with al Qaeda. Most fighters are from inside the country but foreigners brought expertise and were misguiding and misleading young Yemeni people." Early last month a group of 12 Saudis and a Yemeni killed two Saudi security guards in an ambush as they tried to cross into Yemen, leading to the deaths of four of the men and the capture of the others, Saudi state media said.Security experts say Saudi Arabia, under the direction of its Interior Minister Prince Mohammed bin Nayef and intelligence chief Prince Bandar bin Sultan, has a strong presence in Yemen helping the government to infiltrate AQAP."There's full coordination between the counterpart services of the two countries to share information. There are different forms of units to co-ordinate," Ahmadi said.In April a Saudi diplomat was kidnapped by al-Qaida in Aden and is still being held. Another was shot dead near his home in Sanaa last month.But the group's Yemeni wing, which has plotted attacks on international airlines and sworn to bring down Saudi Arabia's monarchy, had sleeper cells on top of this that authorities had yet to track down, he told Reuters on Sunday.Ahmadi accused Tehran of backing the Houthi rebels who operate in northern Yemen near the border with Saudi Arabia - the world's top oil exporter which is competing with Shi'ite Iran for regional influence."Iran seized a chance to broaden the conflict to play a certain role," he said. "We have no hostility to Iran; all we ask is that they don't interfere." "We have processed evidence of their presence and we have arrested a number of people and have sufficient evidence they are interfering," Ahmadi added in an interview on the sidelines of a conference in Bahrain.Iran has already denied interfering in Yemen's affairs.The Houthi movement, named after the tribe of its leader, says it represents the claims of Zaydi Shi'ite Muslims who ruled Yemen for over 1,000 years. Most Iranians follow a different Shi'ite sect but Yemeni officials say Houthis have traveled to Iran's seminary city of Qom for indoctrination.Yemen said in July it had arrested members of a spy ring led by a former commander in Iran's Revolutionary Guard, the state news agency Saba said, adding that the cell had operated in the Horn of Africa as well as Yemen. An Interior Ministry official said all those detained were Yemenis.Houthis have survived repeated government attempts to crush them. They fought a brief war with Saudi Arabia in 2009 after their conflict with Yemeni forces spilled across the border.Sanaa has invited them to join Yemen's national dialogue process aimed at reconciling the disparate groups that emerged before and during a political crisis last year.