HANOI, Vietnam -- Vietnamese police have arrested another blogger, her mother and diplomats said Friday, as authorities continued a crackdown against writers who have criticized Communist Party policies online.

Authorities arrested Nguyen Ngoc Nhu Quynh, 30, who writes under the pen name Me Nam, on Wednesday night at her home in Nha Trang, foreign diplomats said on condition of anonymity, citing protocol.

Quynh's mother, Nguyen Thi Lan, said police arrested her daughter around midnight, arriving at the house while she was sleeping with her child, who is almost 3. She said they accused Quynh, a tour guide, of violating national security laws.

Lan said more than two dozen officers came to the house. About half came inside to read the arrest order, while others waited on the street.

The diplomats confirmed the arrest and said another blogger known as "Sphinx" had also been questioned in connection with her case.

Quynh's arrest was the latest in a series of police moves against writers who had criticized government policies toward China, Vietnam's powerful northern neighbour.

All of them had criticized the government for its backing of a controversial bauxite mine in the Central Highlands, to be built by a Chinese company. They also spoke out against the government's handling of territorial disputes with China over the Spratly and Paracels archipelagos in the South China Sea.

According to Lan, police had previously questioned her daughter about T-shirts she had made saying, "No Bauxite, No China; Spratlys and Paracels belong to Vietnam."

On August 25, one of Vietnam's most popular bloggers, Huy Duc, was fired by the Saigon Tiep Thi newspaper after the Communist Party complained about his blog, "Osin."

Two days later, authorities detained 37-year-old Hanoi blogger Bui Thanh Hieu, who has been critical of the Communist Party's handling of relations with China and land disputes with the Roman Catholic Church.

The next day, police in Hanoi arrested Doan Trang, 31, a writer for the popular online newspaper VietnamNet.

The government tightened its rules for bloggers earlier this year, saying they must restrict their writings to personal matters.