Chinese steel, iron ore rise after Beijing says to keep supporting economy

* China to keep econ support despite better-than-expected growth

* Tangshan issued second level smog alert for April 20-25

* Market expects Tangshan to tighten production curbs

BEIJING, April 22 (Reuters) - China’s steel and iron ore futures rose nearly 3 percent on Monday after last week recording their worst weekly performance in several months, buoyed after Beijing said it would maintain policy support for the economy.

A top decision-making body of the Communist Party on Friday said that support would come as China’s economy still faces “downward pressure” and difficulties despite better-than-expected first quarter growth.

The world’s second largest economy last week reported first quarter growth at 6.4 percent as industrial production jumped sharply and consumer demand showed signs of improvement.

More economic stimulus policies are widely expected.

Benchmark Shanghai rebar prices rose 2.9 percent shortly after the market opened. They were up 2.2 percent at 3,795 yuan ($566.09) a tonne by 0147 GMT.

The jump in steel prices was also driven by concerns over tight supply as the top steel-making city of Tangshan issued a second-level smog alert, effective from April 20 to April 25.

Steel mills in the Chinese city were ordered to halve their shaft furnace operations and halt sintering machines by at least 40 percent or even shut down, based on their emission levels, during the alert.

Meanwhile, analysts generally expect Tangshan to tighten its anti-smog measures in the coming months, which could curb supplies in the market.

“If Tangshan strictly implements production restrictions in May, we would see steel supply falling more sharply than demand,” Gu Meng, analyst from Orient Futures, said in a note.

“With increasing steel prices and therefore profit-margins at mills, prices of steel-making raw ingredients will also go up despite decreasing demand,” the analyst added.

The most-traded iron ore contract on the Dalian Commodity Exchange, for September delivery, climbed 2.4 percent to 634 yuan a tonne.

Coking coal prices advanced 0.9 percent to 1,335 yuan a tonne, while coke futures were up 1 percent at 2,052.5 yuan. ($1 = 6.7039 Chinese yuan renminbi) (Reporting by Muyu Xu and Dominique Patton; Editing by Joseph Radford)