UPDATE 2-EU exec opens antitrust probe into eight cement firms

* EU probe includes price fixing, market sharing

* Probe also covers possible blocking of imports and exports

* World’s top four cement makers investigated

* Lafarge, HeidelbergCement shares down

(Recasts lede, adds shares, background)

By Foo Yun Chee

BRUSSELS, Dec 10 (Reuters) - EU antitrust regulators opened an investigation on Friday into the world’s top four cement manufacturers and four other producers suspected of colluding to fix prices and block foreign imports.

The European Commission did not identify the firms, but France's Lafarge LAFP.PA, Switzerland's Holcim HOLN.VX, Mexico's Cemex CMXCPO.MXCX.N, Germany's HeidelbergCement AG HEIG.DE, Italy's Buzzi Unicem BZU.MI and its Dyckerhoff unit DYKG.DE all said they were subject to the investigation.

The probe followed raids by the European Union executive on several companies in September last year and in November 2008. World number three producer Cemex said on Thursday that it and seven other firms were under investigation. [ID:nLDE6B903M]

“The Commission intends to investigate in particular possible import/export restrictions, market sharing and price coordination in the markets for cement and related products,” the EU executive said in a statement.

World No. 4 HeidelbergCement shares were down 3.8 percent to 44.91 euros by 1354 GMT, underperforming a 0.1 percent weaker Stoxx 600 European Construction and Materials index .SXOP, with one analyst citing the EU probe as a factor.

Top producer Lafarge was 1.2 percent lower at 46 euros, world No. 2 Holcim and Buzzi Unicem reversed losses to trade up.

The EU regulator said its probe included firms in Austria, Belgium, the Czech Republic, France, Germany, Italy, Luxembourg, the Netherlands, Spain and Britain and related to cement, cement-based products and other materials.

Germany’s HeidelbergCement AG also denied the allegations.

“HeidelbergCement is working with the EU Commission and has, on multiple occasions, supplied the Commission with material (to aid the investigation),” it said in a statement.

“HeidelbergCement expects to be able to prove the allegations to be unfounded.”

Lafarge said it had been contacted by EU investigators, but said the mere fact of an investigation did not mean there was any proof of wrongdoing. Holcim confirmed it was being investigated but would not comment further.

Buzzi Unicem said the regulator requested information for 2000 to 2010. It said it would supply information for Italy, while Dyckerhoff would provide details on its operations in Belgium, Czech Republic, Germany, Luxembourg and the Netherlands.

The Commission can fine companies up to 10 percent of global turnover for breaching EU antitrust rules.

It imposed a total fine of 478 million euros ($633 million) on Lafarge, Britain’s BPB, Germany’s Knauf and Belgium’s Gyproc in 2002 for operating a cartel in the market for plasterboard for builders. [ID:nLDE65G0NN]

The Spanish watchdog is also conducting its own investigation into Cementos Portland CPLN.MC, Cemex Espana, Cetya, Vresa and Hormigones Beriain. (Editing by Rex Merrifield and Mike Nesbit) (Additional reporting by Josie Cox in Frankfurt and Gilles Guillaume in Paris, Nigel Tutt in Milan and Oliver Hirt in Zurich) ($1=.7551 euros)