Vietnam is estimated to export 2.2 million tons of rice in the first half of this year, down from 2.9 million tons in the same period last year, according to a local trade agency on Monday.

Local rice exporters have already signed contracts of shipping abroad some 4 million tons of rice, the Export-Import Department under the Trade Ministry said, noting that the government has recently decided that the rice export volume should be within 4-4. 5 million tons this year to ensure domestic food security.

Vietnam, the world's second largest rice exporter, shipped over 4.7 million tons of rich worth 1.3 billion U.S. dollars last year to nearly 100 markets, with the exports to the Philippines, Malaysia and Cuba accounting for some 60 percent of the total.