Former European colonies have threatened to block a trade deal to reduce the EU's controversial tariffs on Latin American banana imports.The African, Caribbean and Pacific (ACP) trade grouping said the 35% cut agreed by EU and Latin American officials on Sunday was unacceptable.An ACP spokesman said the group would present a counter-proposal on Monday.The negotiations took place during World Trade Organization talks in Geneva about a new global trade deal.On Sunday, a spokesman for EU Trade Commissioner Peter Mandelson said there had been "very substantial progress" on the dispute over banana imports to the EU.The bloc has been accused of giving preferential treatment to its members' former colonies.UndercutEU officials have been trying to review the special trade deals with about 80 ACP countries, which have been in place since the 1950s.These deals have allowed a range of products, including banana crops from ACP states, to enter the EU with no duty to pay, while Latin American exports were charged.On Sunday, the EU and Latin American exporters agreed to further reduce the EU's import duty to 114 euros ($179; £90) a tonne by 2016 - a 35% cut.But Cameroon's Trade Minister, Luc Mbarga Atangana, - speaking on behalf of banana exporters in the ACP group - said the deal was unacceptable in its current form.Lowering EU import tariffs further could devastate ACP banana output, some countries warn.Meanwhile, some senior politicians in Italy, France and Ireland have said they are worried about moves which would force them to cut subsidies to their farmers.The WTO's Doha talks for a global trade deal were launched in 2001.Correspondents say they risk further years of delay unless there is a breakthrough in the coming days.