Credit: FB Bronson Kaahui

Hundreds of Vietnamese have taken to the streets to protest the massive fish deaths that have occurred recently. Some have said it was related to discharge from a newly built Taiwanese steel plant by Formosa Plastics, though the government said there is no evidence of this link.

"On Thursday, Facebook users called for peaceful protests to highlight food security and environmental concerns sparked by the deaths, while a petition on the White House website urging help from the United States drew close to 100,000 signatures.

Signers want President Barack Obama to raise the issue with the government when he visits Vietnam next month, and sought help in doing an independent environmental impact assessment of the steel plant.

Tests of seawater in Thua Thien-Hue, one of the affected provinces, showed higher than normal levels of some pollutants, the province's environment department has said.

Vietnam has a four-day holiday ending Tuesday, and many people had booked tours to beaches in Quang Binh, neighboring the province of Ha Tinh. The latter, 400 km (250 miles) south of Hanoi, is where dead fish began washing up on April 6.

Seafood markets have been deserted and tourist firms are receiving cancellations, state media reported."