Officials in the Polish city of Grudziadz prepared during the weekend for another round of protests by farmers angry over low cereal and oilseed prices.

Leaders of the northern city of 96,000 have established a crisis management team to deal with disruptions, after farmers announced they would hold a week of protests, Polish Radio reported Saturday.

A local farmers' union Thursday shut down a bridge over the Vistula River in Grudziadz and blocked the highway to Gdansk Friday.

The farmers brought life in the city to a halt as dozens of tractors carrying black coffins -- what the protesters called symbols of the collapse of Polish agriculture -- blocked traffic.

The farmers are demanding higher prices for cereals, oilseed and livestock, as well as the establishment of minimum prices at a time when futures for rapeseed fell to three-year lows due to a jump in European Union supplies -- which in turn has sparked selling from farmers worried over even lower prices ahead.

The National Farmers Protest Committee said members would block highways again this week, including one on a stretch between the city and the local airport, the broadcaster reported.

The group claims Poland is importing large quantities of cheap rapeseed oil from Ukraine, making its production in the country unprofitable.

They suspect it is grown on contaminated land in and around Chernobyl, scene of the 1986 nuclear disaster.

"When manufacturers and consumers find out that these food products are produced from contaminated lands (in Ukraine), they will not buy them," Paul Barczak of the National Farmers Protest Committee told Polish Television.

A negotiating session Friday among the farmers' group, Polish Deputy Minister for Agriculture Tadeusz Nalewajkiem and Kuyavian-Pomeranian Gov. Ewa Mes broke down after the farmers demanded a halt to Ukrainian imports.

Polish Television reported the meeting devolved into angry shouting matches when government officials wouldn't commit to making statements supporting the call for a suspension of rapeseed imports.

"We need to think, calculate with a pencil in hand, and not expect that something will happen (immediately)," Mes said.

Nalewajkiem said he would take the farmers' demands to the Minister of Agriculture, but warned specific decisions would have to wait.

"It is not possible today to ensure prices -- the market decides," he said. "I'll monitor the Ukrainian market, and if something arises, then we will ask for blocking imports."

The Polish news agency PAP reported Nalewajkiem stressed the low prices for grain and oilseed are global, due to plenty of grain on the market.

It's impossible to meet demands to prohibit grain imports from Ukraine due to World Trade Organization agreements, he said, noting the country's trade relations with Ukraine are reciprocal -- Poland, he noted, exports a large amount of apples and poultry to Ukraine, PAP reported.

Mark Duszynski, co-organizer of the protest, told reporters the situation will result in destitute farmers taking their own lives.

"Now, a ton (of rapeseed) produces just ($282), or about half as much as a year ago," he told the Pomeranian Gazette. "It is, after all, not enough to survive. You see, it comes down to the fact that rural people will commit suicide."