BEIJING (AP) Snow battering central China has dealt an "extremely serious" blow to winter crops, a top agriculture official warned Thursday, raising the likelihood that future shortages would exaggerate already surging food prices.

Regions hit by the worst winter storms in 50 years provide the bulk of China's winter fruit and vegetables, Chen Xiwen, deputy director of the Communist Party's leading financial team, told reporters.

The full magnitude of the losses was unclear and much depended on the weather in the coming days, he said.

"The impact of the snow disaster in southern China on winter crop production is extremely serious," Chen said. "The impact on fresh vegetables and on fruit in some places has been catastrophic."

These new shortages have complicated Beijing's struggle to control inflation, much of it caused by already soaring food prices, by increasing supply.

Three weeks of continual snow and ice storms have paralyzed much of central and eastern China, paralyzing railways, closing highways, and killing dozens in road accidents and collapsed buildings.

Train service was returning to normal on Thursday, thinning the massive crowds that have been waiting to go home for next week's Lunar New Year a holiday that is as important in China as Christmas is in the West.

Hundreds of thousands of Chinese have been stranded over the past days because of the blizzard. But the Railway Ministry said Thursday service had basically returned to normal on the vital Guangzhou to Beijing line one of the worst hit and extra trains were being put on the schedule.

Chen said the storms' overall effect on agriculture depended on how long the storms lasted and whether they moved into northern China, which produces most of the country's wheat crops.

"If it heads northward, then the impact on the whole year's grain production will be noticeable," Chen said.

The Civil Affairs Ministry said Tuesday the storms, which began Jan. 10, had already cost China $3 billion. In addition to agriculture, fish and poultry farms have also been hard hit, and much industrial production is at a standstill.

Wholesalers in Beijing said only about 20 percent of the usual supply of fresh vegetables was reaching the city. Much of China's winter produce is grown in plastic-sheeted greenhouses that have collapsed under the snow.

Coupled with crop destruction, transport delays have helped drive up vegetable prices nationwide, with those in the hardest hit areas more than doubling.

In the central city of Zhengzhou, tomatoes have doubled in price, and in nearby Shenzhen, the cost of vegetables rose by a third, on average, local media reported. Lamb and other meat prices have also soared in the southern transport and manufacturing hub of Guangzhou, the reports said.

Even before the storms, prices had risen by double-digit rates over the past year, and the government had vowed to increase supply to lower those prices and the resulting inflation.

In December, consumer prices were 6.5 percent higher than during the same period the year before.

The government responded to these price hikes with a variety of measures, from freezing prices for a slew of goods, to boosting farm subsidies and curbing industrial use of corn.

Fuel prices have also increased, with anthracite coal, used for household heating, rising by 75 percent.

Authorities have ordered that priority be given to coal and food shipments, with all tolls, fees and restrictions waived.

The country's top leaders have also deployed more than 450,000 army troops and extra units of police to clear roads and help provide emergency supplies to the millions of stranded travelers, state-run media reported, saying authorities had declared an "all out war" on the crisis.

The storms have caused dozens of deaths and airport closures. China's antiquated power grid, powered largely by coal, ground to a near halt, plunging many cities into darkness.