By Rozanna Latiff and Prak Chan Thul
KUALA LUMPUR/PHNOM PENH (Reuters) - Malaysian authorities have detained an official of a banned Cambodian opposition party, rights officials said on Thursday, after neighboring Thailand blocked her bid to return home and Cambodia sought her arrest after a news conference in Indonesia.
Mu Sochua, the vice-president of the Cambodia National Rescue Party (CNRP), was held at the airport in the Malaysian capital ahead of her return, intended by Saturday, along with that of the party's founder, Sam Rainsy.
"She is in the immigration holding room at KLIA," said Jerald Joseph, an official of the Malaysian Human Rights Commission, referring to the airport in Kuala Lumpur.
Joseph said he spoke on Wednesday with Sochua, who had been told she would not be deported to Cambodia. It was not immediately clear where authorities would send her next.
Last week, Thailand turned away Sochua when she flew into Bangkok's main international airport. She later flew to Indonesia, where the Cambodian embassy on Wednesday asked for her to be arrested after she held a news conference.
Malaysia's immigration department did not immediately respond to questions from Reuters.
In Cambodia, a senior CNRP member said the party was not aware of Sochua's detention in Malaysia.
Cambodia has arrested at least 48 opposition activists this year over accusations of plotting to overthrow the government of Prime Minister Hun Sen.
Dozens of other opposition activists who fled Cambodia, fearing arrest, have vowed to return in support of Rainsy.
In Jakarta, asked how the Cambodian government felt about the return of the activists, Sochua told the news conference that the Cambodian authorities were "totally threatened beyond borders".
She added, "From here I am going to Malaysia and they will follow me, they will follow us, all the way.
"What do they fear? They totally fear the determination of the people of Cambodia who are responding positively to our appeal, which is, 'Together, we will build a better Cambodia.'"
Sochua's detention in Malaysia was ludicrous and unacceptable, said New York-based Human Rights Watch (HRW).
"She's done nothing wrong and should be immediately released and allowed to undertake the consultations she planned with the Malaysia government and civil society groups," said Phil Robertson, the group's deputy director for Asia.