* Probe launched into several Koc-owned firms
* One of group's hotels sheltered protesters
* Finance minister says no link to demonstrations (Adds analyst comment, background, updates shares)
By Humeyra Pamuk and Evrim Ergin
ANKARA/ISTANBUL, July 25 (Reuters) - Turkey's government haslaunched a probe into the tax affairs of energy firms affiliatedwith one of the country's most prominent business dynasties,weeks after criticising one of the family's hotels forsheltering protesters during anti-government unrest.
Police and finance ministry tax inspectors late on Wednesdayraided the offices of Tupras, Turkey's sole refiner,and energy company Aygaz, both of them controlled byconglomerate Koc Holding.
Shares in all three companies fell more than 3 percent,extending losses from late on Wednesday.
Finance Minister Mehmet Simsek said there was no connectionbetween the probe and last month's demonstrations. Fuel retailerOpet, also owned by Koc Group, and a joint venture between RoyalDutch Shell and Turkish Turcas Petrol werealso part of the investigation.
"Ministry of Finance tax inspectors carry out around 50,000inspections a year. There is absolutely no linkage between (lastmonth's) protests and current tax probes," Simsek said on hisTwitter account.
An official at the Shell-Turcas joint venture said heexpected the investigation to continue until the end of themonth.
The Koc family are one of the most prominent dynasties amonga secular business elite in Turkey which has at times had anuneasy relationship with Prime Minister Tayyip Erdogan'sIslamist-rooted AK Party.
The family owns five of Turkey's 10 largest companies.
Erdogan has criticised the Divan Hotel, owned by Koc, foropening its doors to shelter protesters fleeing police tear gasduring weeks of violent anti-government demonstrations lastmonth and some analysts had warned it could face sanctions.
Koc declined to comment on the investigation.
The protests began as a peaceful campaign againstredevelopment plans for Gezi Park, a small, leafy corner ofcentral Istanbul, but spiralled into a broader show of defianceagainst what demonstrators said was Erdogan's authoritarianism.
The unrest, in which police fired tear gas and water cannonnight after night, dented Turkey's image of stability on theedge of the volatile Middle East.
PRECEDENT
Erdogan's government has in the past levied heavy tax finesand seized the assets of media firms perceived to be critical ofhis administration. The government has denied any politicalmotivation in such cases.
Dogan Holding, once Turkey's largest media group, was finedover $2.5 billion for alleged tax evasion in 2009. But the caseslipped under the radar after Dogan, which also has energy,manufacturing and finance interests, sold two dailies and atelevision channel as part, it said, of a routine restructuring.
Tupras said in a statement that checks had been carried outon physical inventories including fuel feedstock, refined oilproducts as well as lube oil as part of the probe.
An official from Turkey's energy watchdog EPDK said thefinance ministry had asked it for information but added that theprobe was not part of regular EPDK inspections.
Tupras shares initially fell more than 6 percent in earlyactivity on Thursday but recovered some of their losses to tradedown 3.5 percent by 1100 GMT.
Koc Holding and Aygaz were down 3.2 percent and 3.7 percentrespectively, underperforming the broader Istanbul share index, which fell 1.56 percent.
Erdogan has rounded on a number of companies for theirperceived support of the protests, and investors said they wouldbe watching to see whether other probes are announced.
"If the investigation spreads to other companies, it will benegative for capital markets," said Ali Bahcuvan, head of theStock Market Investors' Association.
Fellow family-run conglomerate Boyner came under fire afterits chairman posed in a photo with a demonstrator's placard.
The country's third-biggest lender Garanti Bank saw a small number of customers cancel credit cards in supportof the demonstrations after a sister media firm gave them scantcoverage, but later found itself the subject of government ireafter one of its executives voiced sympathy for the protesters.
"Erdogan has already singled out some businesses like theKoc Group, Boyner and Garanti Bank," Eurasia Group analyst NazMasraff said in a note last week, ahead of the probe.
"These companies may be used as scapegoats as Erdoganapplies direct or indirect sanctions against them." (Additional reporting by Birsen Altayli in Istanbul; Writing byNick Tattersall; Editing by Dale Hudson)