BEIJING, Feb 15 (Reuters) - China's state planner will hold what it called a "reminding and warning" symposium with domestic and foreign iron ore traders on Feb.17 in an effort to ensure market stability, according to two sources and a notice reviewed by Reuters.

Iron ore prices have been diving since last Friday after regulators and the industry association vowed to take measures to stabilise the market.

The National Development and Reform Administration (NDRC), together with the market regulator, will summon traders including five Chinese iron ore trading firms such as RGL Group and Tangshan Haichi, as well as five foreign traders like Glencore, Mercuria and Itochu, in Qingdao in Thursday morning, according to an NDRC notice reviewed by Reuters.

The state planner declined comment when asked by Reuters about the meeting on Thursday.

A sales manager surnamed Zhang from Tangshan Haichi confirmed the company had received the notice and said their general manager will attend the meeting with certain data it has been asked to submit.

Another contact from the iron ore trading department of Mercuria, who declined to be named, said the NDRC asked participating companies to provide their portside iron ore inventories in China, and details of their recent trading in the spot and futures markets.

The NDRC held a meeting with the market regulator and securities regulator on Tuesday to learn about iron ore stockpiles and recent transactions in state-owned companies such as China Minmetals, Xiamen ITG and AVIC International, and asked them to take responsibility in helping the government stabilise prices.

The most-traded iron ore futures on the Dalian Commodity Exchange hit their lower-trading limit of 10% on Tuesday afternoon to 699 yuan ($110.04) per tonne and logged their biggest loss since May 20.

The front-month March contract of iron ore on the Singapore Exchange tumbled as much as 13.8%.

($1 = 6.3525 Chinese yuan renminbi) (Reporting by Min Zhang and Dominique Patton, additional reporting by Beijing Newsroom)