April 11 (Reuters) - Apple ( AAPL ) was pressed on

Thursday to take action on Vietnam's detention of climate

experts, with activist organizations saying it should weigh in

given that the country has become a key manufacturing hub for

the iPhone maker.

In a letter to Apple ( AAPL ), more than 60 human rights and

environmental rights organizations highlighted the Sept. 15

detention of Ngo Thi To Nhien, the executive director of the

Vietnam Initiative for Energy Transition (VIET), an independent

think tank focused on green energy policy.

Before her detention, Nhien had worked with the Vietnamese

government and international organizations on the country's

energy transition towards renewable energy, according to

Bangkok-based advocacy group Project88, one of the rights groups

that signed the letter.

Vietnamese authorities have accused Nhien of improperly

accessing documents. At least five other climate experts have

been detained, accused of tax fraud.

Activists say the charges have been trumped up. The United

States and the United Nations have also criticized the

detentions of climate activists.

"Since Vietnam is now Apple's ( AAPL ) most important production hub

outside of China and has committed to human rights and 'equity

and justice in climate solutions,' we believe you have a

responsibility to weigh in," the rights groups wrote in the

letter to Apple's ( AAPL ) executives and board of directors.

"Indeed, by not making a public statement on this matter,

you risk violating your own environmental and human rights

policies and delegitimizing Apple's ( AAPL ) positive work in these

areas."

Apple ( AAPL ) manufactures iPads, AirPods and Apple Watches in

Vietnam and suppliers for MacBooks are also investing in the

country.

Apple ( AAPL ) has in the past called on the Vietnamese government to

make it easier for businesses to purchase energy directly from

renewable power projects and has supported a power development

plan in Vietnam that would prioritize clean energy.

The company has also at times provided financial support to

human rights activists through work with the Fund for Global

Human Rights.