Police in the Vietnamese capital Hanoi have arrested trade unionist Vu Minh Tien, according to The 88 Project, an international nonprofit that campaigns for freedom of speech in Vietnam.

Tien is head of policy and legal affairs at the Vietnam General Confederation of Labor and director of the Institute for Workers and Trade Unions, the group said.

Tien was being held under Article 337 of Vietnam’s criminal code, which covers “deliberate disclosure of classified information; appropriation, trading [and] destruction of classified documents,” the group said.

Tien was last seen in public at a workshop in Ho Chi Minh City on March 21, The 88 Project said.

News of his arrest follows the detention on April 24 of Nguyen Van Binh, director general of the Labor Ministry’s legal department.

Binh was arrested for disclosing state secrets under Article 337, according to state broadcaster the Voice of Vietnam.

Vietnam only has one state-affiliated union. The two unionists were working to bring labor law in line with international standards by ratifying International Labour Organization Convention 87 which allows workers to form unions, The 88 Project said.

“These arrests are yet another example of the failure of international organizations to say a mumbling word about the advocates and reformers they are so keen to champion until these people wind up in jail,” said the group’s co-director, Ben Swanton.

He called on the International Labour Organization, the European Union and the United States to immediately issue public statements condemning Vietnam for arresting the trade unionists.

“Western governments that claim to care about human rights need to break their silence about Vietnam’s policy of violating those very same rights,” Swanton said.

Radio Free Asia phoned Vietnam’s Ministry of Foreign Affairs to ask about Tien’s arrest but no one answered. A call to the Vietnam General Confederation of Labor was also not answered.

International nonprofit CIVICUS joined calls for the unconditional release of Tien and Binh.

“These arrests highlight the systematic targeting of human rights defenders in country by the regime and makes a mockery of Vietnam’s membership of the Human Rights Council,” said CIVICUS Asia researcher Josef Benedict referring to Vietnam’s place on the United Nations rights body for a three-year term.

“We call on the international community to speak up, especially the EU, and push for the release of the two union activists and for greater freedom for trade unions in the country.”