* China steel futures hit a 19-month high last week
* Steel futures fall after exchanges raise trading costs
* Investors pull back speculative buying, cooling the market
* Iron ore futures and spot fall (Updates close prices)
SHANGHAI, April 25 (Reuters) - Shanghai steel futures fell on Monday from a 19-month high after China's commodity exchanges took measures to crack down on speculative buying and amid a technical pullback following last week's surge.
Domestic commodity exchanges raised transaction costs for some volatile futures contracts, including rebar and iron ore, to stem demand. The move marked the second time this year that the margin for iron ore futures has been lifted. most active rebar futures on the Shanghai Futures Exchange SRBcv1 inched down 0.3 percent to close at 2,643 yuan ($406.20) a tonne.
A rapid rise has pushed the contract to the highest since June 2015 last week. It has risen 54 percent so far this year.
"The exchange's moves are having an impact on markets, as the rally was believed to be driven by financial investors more than fundamentals," said Zhao Chaoyue, an analyst with Merchant Futures in Shenzhen.
"Steel mills, traders and investors have become concerned about the gains, which are too fast and the market needs cooling, but I am still positive on the long-term outlook as Beijing's supply-side reform will gradually take effect."
However, some analysts are concerned the steel price rally will be unsustainable given a lack of strong demand recovery despite rising steel production.
Fitch rating agency put the rapid increase in Chinese steel prices down to a seasonal pick up in construction and elevated speculation in futures, but said increased supply would put significant pressure on prices in the near term. government has moved to cut the overcapacity but the rally in steel prices has driven some zombie mills to return to production, which will put more pressure on Beijing to slash output. ore futures on the Dalian Commodity Exchange DCIOcv1 dropped 0.7 percent to 471 yuan a tonne by close.
Iron ore for immediate delivery to China's Tianjin port .IO62-CNI=SI slumped nearly 5 percent to $65.50 a tonne last Friday after soaring to a near 16-month high of $68.70 in the previous session.
The spot benchmark has gained 53 percent so far this year.
($1 = 6.5067 Chinese yuan renminbi)