FACTBOX - Five facts about Afghanistan's Helmand province

(Reuters) - July could become the bloodiest month in the 8-year-old Afghanistan war as casualties mount after U.S. and British troops mounted major operations in Helmand province.

Helmand has been the Taliban's opium-producing heartland.

Some 10,000 U.S. Marines launched Operation "Strike of the Sword" this month in the province's southern half, while a similar-sized British-led task force launched operation "Panther's Claw" to the north.

Following are five facts about Helmand province.

* Helmand is Afghanistan's largest province, about 60,000 sq km (23,000 miles), making it nearly as large as the Republic of Ireland. At least 43 foreign soldiers have already died this month as U.S. and British troops simultaneously launched the two biggest operations of the war to seize the province.

Canadian, Dutch and other NATO troops had been fighting alongside some 9,000 British troops in Helmand but U.S. military commanders had described the combat situation in the past year as a stalemate. Existing force levels had not been able to cope with the size and difficulty of the terrain, which includes wide deserts in the south and mountains in the north. In May, the deputy commander of NATO-led forces in the south warned of "a bloody summer ahead."

* Helmand's population is mainly made up of Pashtuns, Afghanistan's largest ethnic group who have also traditionally been the country's power brokers. It borders Pakistan to its south, Kandahar province to its east and Nimroz province to the west, all mainly Pashtun provinces and heavily influenced by the Taliban. Provincial officials estimate four out of Helmand's 13 districts are under Taliban control.

* Helmand produces more than half of the opium cultivated in Afghanistan, the source of about 90 percent of the global supply, according to the United Nations Nations Office on Drugs and Crime. In 2008 more than 103,000 hectares of poppy were cultivated. The drug crop is closely tied to the insurgency and the Taliban are mainly funded by the opium trade.

But NATO forces in Afghanistan are not permitted to engage in crop eradication, a policy that limited British tactics in crippling the insurgency. Britain, the United States and other NATO allies have started a number of civilian programmes to offer farmers alternative crops to opium, such as wheat, but Helmand remains Afghanistan's biggest poppy-producing province.