Governments opposed to the EU climate levy on international aviation have agreed a limited package of counter-measures during a meeting in Moscow. But they will not immediately lodge a case against the EU for breach of UN rules, as had been proposed. The 23 nations issuing a joint declaration include the US, China, Brazil, Japan, Saudi Arabia and Russia. An EU spokesman said the bloc would welcome joint moves towards a global deal on fast-rising aviation emissions. Governments at the Moscow meeting were protesting against an EU law that came into force in January. It means that all airlines have to add up greenhouse gas emissions from flights that begin or end at EU airports, and must pay a small charge or trade carbon permits on the EU Emission Trading Scheme (ETS) if they exceed their allowance. Airlines also have to pay for 15% of their allowance. The caps will be tightened over time, increasing incentives for aircraft manufacturers and operators to become more fuel-efficient. China has banned its airlines from taking part in the scheme, which could lead to them being fined or barred from European airspace. Russia and the US are debating similar moves, and there have been fears that the issue could lead to a trade war, despite the small sums of money airlines will have to pay. Calculations suggest the measure would add $2-3 per transatlantic flight, which is far smaller than existing levels of taxation levied by governments. A draft declaration drawn up earlier this month indicated that opponents would immediately file a legal challenge to the EU under the Chicago Convention, the 1944 agreement on aviation rules. Among other things, it says that each nation has sovereignty over its own skies, and that aviation fuel is exempt from taxation. The 23-nation group say the EU\'s inclusion of international flights in the ETS breaches the convention. But the declaration issued at the end of the two-day meeting merely says countries will \"consider taking actions... including, for example, a proceeding under... the Chicago Convention\". It also says they will \"continue their intensified common efforts\" to agree global measures limiting CO2 emissions from aviation within the International Civil Aviation Organization (ICAO), and \"strongly urges the EU member states to work constructively in ICAO\" to achieve such an end. Fast growth It was partly in frustration at the failure to get an agreement at ICAO, despite 14 years of talks, that the EU enacted its unilateral legislation. And Isaac Valero-Ladron, the European Commission spokesman for climate action, agreed that work should go forward. \"Let\'s be honest; what came out from this [Moscow] meeting? Nothing new and nothing concrete for the climate,\" he told BBC News. \"The serious work to reduce global aviation emissions should continue at ICAO. If these countries meeting in Moscow are serious about getting a global agreement on action, then let\'s get it done!\" The EU says it would suspend its measures in the event of a global agreement that had equal impact on emissions. In December, the European Court of Justice ruled the EU levies were legal under international law. Currently, aviation accounts for only about 2% of the world\'s greenhouse gas emissions. But they are rising faster than any other sector, despite the increasing efficiency that manufacturers have achieved in recent years.