(Adds details, background)
By Kaweewit Kaewjinda
BANGKOK, July 31 (Reuters) - Thailand's junta on Thursday named a majority of active and retired members of the security forces to an interim legislature of 200 people, as it seeks to keep tight control over the body it will task with enacting sweeping reforms.
The armed forces took power on May 22 in a bloodless coup following six months of street demonstrations that contributed to the ousting of Prime Minister Yingluck Shinawatra.
The junta had been widely expected to reserve both the majority of the interim legislature and the cabinet for the security forces to keep a tight grip on power during a transition back toward a civilian government.
The assembly will appoint a prime minister to choose a 35-member cabinet. The prime minister is likely to be the commander who led the May 22 coup, General Prayuth Chan-ocha, sources told Reuters this week.
He is expected to award top portfolios to members of the junta, known as the National Council for Peace and Order (NCPO).
The list of 200 members was read out on national television in an evening junta broadcast, which said the National Legislative Assembly (NLA) would hold its first meeting on August 7. Prayuth has said a cabinet will be formed in September.
The transition, mapped out in an interim constitution promulgated last week, offers the NCPO immunity and broad powers to overrule the interim government and the NLA.
The broadcast disclosed no further details beyond the names of the members and the date of the NLA's ceremonial opening. The constitution provides for a maximum of 220 assembly members so further appointments may be made later.
No official list clearly identifying the backround and qualification of members was available. A tally established by Reuters showed 116 current or past members of the security forces - 105 military and 11 from the police.
Since taking power, the junta has purged officials linked to Yingluck and her brother Thaksin, a former premier himself and the power behind Yingluck's government.
The junta says reform is needed to end years of instability and prevent a repeat of the six months of sometimes violent protests that paralysed Yingluck's government. The interim cabinet and NLA will enact the reforms before calling elections late next year.
Some analysts and supporters of the ousted government say the reforms the military wants to undertake were the goals of protesters who tried to topple Yingluck's government.
The protesters wanted changes that would eradicate the political power of the Shinawatra family, which controls a populist political machine that has won every election since 2001 with rural and working-class backing.
The interim constitution provides a framework for stringent political control last exercised by the military in 1970s and 1980s, when it oversaw an era of military-managed democracy after a succession of coups and weak coalition governments.
The military is keen to prevent a repeat of the mistakes of its 2006 putsch and 2007 constitution re-write. Both failed to weaken the influence of the self-exiled Thaksin, the nemesis of the army-backed royalist establishment.
Thaksin's governments have been toppled three times by coups or courts since 2006, interventions his allies say were orchestrated by a conservative oligarchy threatened by his clique of upstart businessmen.
Another military source said members of Prayuth's politicised military clique, the "Eastern Tigers" of the Queen's Guard, would take cabinet posts, including retired former army chief Anupong Paojinda as deputy prime minister and defence minister. (Reporting by Kaweewit Kaewjinda; Writing by Simon Webb; Editing by Ron Popeski)