The UN's Food and Agriculture Organisation Friday warned of food security problems in poor countries after Russia halted exports amid a heatwave, saying the global grain price situation was "serious".

Russia's decision "is going to interrupt trade and create instability in the market... a situation which was not serious has now become serious," FAO economist and grain trade expert Abdolreza Abbassian told AFP

"Of course, if prices go up in poorer countries

withlowincome,itwill causeproblems" intermsof foodsecurity,hesaid.

Currently the world's number three wheat exporter, Russia has cut its grain harvest forecast by millions of tonnes and temporarily banned exports of wheat after it saw 20 percent of its arable land scorched by a heatwave.

"In connection with the unusually high temperatures and the drought, I consider it right to impose a temporary ban on the export from Russia of grain and other products produced from grain," Putin told a government meetingThursday.