By Barbara Lewis

LONDON, Feb 16 (Reuters) - Iranian steel imports have become the latest threat to European steelmakers, their trade group said on Thursday, after imports from Iran rose by nearly eight times between 2013 and 2016.

Steel lobby group Eurofer said on Thursday that Iranian exports to Europe had leapt to just over 1 million tonnes annually, putting the country just behind India at 1.9 million tonnes, while China shipped 5.7 million tonnes in 2016.

"The threat from Iran is new and it's going to be one of the top three issues: China, India, Iran," Karl Tachelet, external relations and trade director at Eurofer, told Reuters.

Iran has sought to boost its steel sector, with help from foreign partners, as it targeted economic expansion following the 2015 deal to curb Iran's nuclear programme in return for an easing of sanctions.

But Tehran has said it is considering export duties on iron ore, as India has done, which would increase the availability of cheap raw materials for its own steelmakers.

Eurofer, which represents an industry that has to import its iron ore, says that amounts to protectionism. Iranian officials contacted by Reuters for comment did not immediately respond.

On Wednesday, after a two-day conference on steel in Tehran, Iran said it aims to export between 20 and 25 million tonnes annually by 2025 and to increase total output to 55 million tonnes from an estimated 16 million tonnes now.

That compares with a global market of 1.6 billion tonnes.

China, the world's top producer and consumer of steel, is a dominant player in Iran, where other countries have struggled with the complexity of political and logistical hurdles.

And while cutting its own capacity, China has been building steel operations elsewhere, including on the edge of the European Union in Serbia.

The EU is investigating alleged dumping of hot-rolled steel by producers in Serbia and Iran as well as Brazil, Russia and Ukraine.

It has already imposed penalties on China, prompting an angry response and a WTO complaint from Beijing.

Eurofer says EU measures against nations such as China have helped to revive an industry that was deeply in crisis in late 2015 and early 2016 when steel prices were very low.

Prices have since recovered, but industry officials say the market remains fragile and cannot cope with capacity increases, while politicians in Europe balk at capacity reductions.

"A European commodity steel business won't be sustainable in the long term unless the external parameters (such as anti-dumping duties or capacity reductions) change," Wolfgang Eder, CEO of Voestalpine, told Reuters on Wednesday.

(Additional reporting by Georgina Prodhan in Frankfurt; Editing by Alexander Smith) ((Barbara.hm.Lewis@thomsonreuters.com; +44 207 542 2932; Reuters Messaging: barbara.hm.lewis.thomsonreuters.com@reuters.net))