Two top tobacco manufacturers in India have halted production in a row over new health warnings they are required to put on their packaging. From 1 December tobacco firms must carry a graphic image of a mouth with cancer on all their packs in India. ITC and Godfrey Phillips India say they are unclear over the pictures they should be using, but the health ministry denies there is any confusion. It says the firms must use the new warnings immediately or face penalties. India has about 120 million smokers and the government says smoking kills nearly a million people a year. Earlier warnings of an infected lung and a scorpion sign on tobacco packaging are seen as having been too mild to be effective. How much impact the new warning will have remains to be seen. BBC correspondents say India has very high sales of cigarettes purchased singly, which reduces the impact of pictorial warnings as many smokers never actually see them. Anti-smoking activists say sales of cigarettes are more affected by price rises and taxation than by pictorial health warnings. 'Ambiguity' ITC and Godfrey Phillips India say they stopped production at all their units on Thursday. "Units [for making cigarettes] are shut because of the ambiguity in pictorial warnings to be carried from 1 December onwards," the Press Trust of India news agency quoted an ITC spokesman as saying. ITC makes popular cigarette brands such as India Kings, Gold Flake and Navy Cut. Output is on hold at all five of its units across India, PTI said. An official at Godfrey Phillips - which makes brands like Four Square, Red and White and Cavanders - said work had stopped at its two India units. A health ministry spokesman told the BBC that the image of a cancer-stricken mouth had been in its notification to tobacco companies of 5 March 2010 and there is no reason for confusion. The government order on the new pictorial warnings has faced stiff resistance from tobacco manufacturers and the deadline for implementing it has been postponed a couple of times. In the past few years, India has come up with stringent rules to curb the use of tobacco. Tobacco-related advertisements are banned and the sale of tobacco products to minors is also an offence. A countrywide ban on smoking in public places came into effect two years ago - although correspondents say it is blatantly flouted and poorly enforced.