* China maintains 7.5 pct growth target for 2014
* Nickel up on speculative positioning, Indonesia ore ban
* Zinc rallies to highest in a year before giving up gains
(Updates with closing prices)
LONDON, March 5 (Reuters) - Nickel climbed to a nine-month high on Wednesday on persistent worries about an Indonesian ban on ore exports and after China's leaders affirmed a solid growth target for the year ahead.
Most metals came off their peaks and several dipped into negative territory on renewed tensions in Ukraine after Russia rebuffed Western demands to withdraw forces in Crimea to their bases.
Metals had climbed early in the day after China's government said it aimed to expand the economy by 7.5 percent this year and would pursue reforms in areas ranging from finance to the environment.
Three-month nickel on the London Metal Exchange hit a high of $15,345 a tonne, its highest since June last year, but pared gains to close up 0.8 percent at $15,270.
Nickel's rally was partly driven by short position holders buying back positions, said analyst Leon Westgate at Standard Bank in London.
"Open interest remains elevated, however those positions are perhaps now coming under pressure given the latest price move, the impact of Indonesia's ore ban and additional concerns over Russia," he said in a note.
Russia is the home of the world's biggest nickel-producing company, Norilsk Nickel.
In Indonesia, around $500 million a month in ore and concentrate exports have stopped since President Susilo Bambang Yudhoyono in January imposed mining rules, including the mineral ore export ban, to force companies to build smelters and process raw materials in the country.
Tsingshan, China's largest stainless steel and nickel pig iron producer, has said that while it has built up 8 million tonnes of ore stocks, sufficient supply for one year, "others are in a more precarious position with smaller players scrambling for material", according to a research report from Macquarie.
ZINC HITS YEAR HIGH
In other metals, zinc hit an intraday high at $2,143.50 a tonne, the loftiest since February last year, before coming off the peak and ending down 0.24 percent at $2,116.
"Zinc continues to remain very well supported, with the backwardation keeping shorts at bay while fresh buying and short-covering activity continue to see prices climb higher," Westgate said.
Copper touched the highest levels in a week at $7,085.75 a tonne in intraday trade before paring gains and closing down 0.3 percent at $7,030. The metal is trading 4.5 percent lower so far this year.
Doubts remain on copper's outlook while demand in top user China has been slow to gain steam following the Lunar New Year. China is the world's biggest consumer of copper, accounting for 40 percent of global refined demand.
A growth target of "7.5 percent helps, but let's be realistic. From GDP alone I would be cautious to get euphoric", said analyst Dominic Schnider of UBS Wealth Management in Singapore.
Taking the shine off the news from China was data showing U.S. services sector growth slowed in February, coming in below forecasts as the employment index fell into contractionary territory for the first time in more than two years.
Aluminium rallied to its highest in more than a month at $1,792 a tonne before paring gains to finish 0.4 percent firmer at $1,775.
Tin dipped 0.24 percent to $23,250 per tonne and lead closed virtually flat, down 0.02 percent to $2,136.50.
Three month LME copper
Most active ShFE copper
Three month LME aluminium
Most active ShFE aluminium
Three month LME zinc
Most active ShFE zinc
Three month LME lead
Most active ShFE lead
Three month LME nickel
Three month LME tin
(Additional reporting by Melanie Burton in Sydney; Editing by Jane Baird, Dale Hudson and David Evans)