European environment ministers made tentative progress on Wednesday in moves to curb harmful carbon emissions, notably targeting planes and ships.

Agreement was secured at a meeting in Luxembourg that the European Union would work towards reducing overall emissions by 95 percent come 2050, instead of the current 80 percent -- but without making any firm commitment.

They also adopted a proposal to push for airliners' emissions to drop by 10 percent and those of ships by 20 percent by 2020. Taken together, these growing sectors account for some five percent of all emissions.

But several delegates said talks on what to do with carbon credits -- unused quotas held by the European Union's newest entrants -- broke down.

It amounted to a direct echo of Tuesday's arguments pitting nine, mainly eastern EU countries led by Poland, against richer, western countries who wanted to commit to concrete offers of financial aid for developing nations going into December UN negotiations in Copenhagen.

The failure of finance ministers to agree either overall figures or how to share the load meant the talks between environment ministers were effectively hamstrung, according to Belgium's Paul Magnette.

"The Swedish presidency dragged out an agreement for the sake of the environment council's credibility," he said, "but it was based on (watered-down) compromises."

Billions of tonnes of CO2 polluting rights -- worth tens of billions of euros theoretically -- are currently available, most held by Russia and eastern neighbours admitted to the EU in 2004.

If these surplus emissions rights are prolonged through the 2013-2020 period that follows expiry of the existing global Kyoto protocol on combatting global warming, Russia and some of these countries might not have to reduce their actual emissions, a European Commission official warned.

EU leaders will have to try and broker agreement on the criticial financing element at a Brussels summit next week.