* Emergencies Ministry says no damage to Sochi's infrastructure
* Putin ordered checks to see if Olympic sites suffered from tremor (Updates with Putin's order to check Olympics sites)
MOSCOW, Dec 26 (Reuters) - Russia's Black Sea resort of Sochi, which will host the 2014 Winter Olympics, has been hit by a gas pipeline blast and a mild earthquake, a government spokeswoman said on Wednesday.
Irina Gogoleva, of Russia's Emergencies Ministry, said no one was hurt and there was no apparent damage to the city's infrastructure after a 5.3 magnitude earthquake was reported at 0242 local time on Wednesday (2242 GMT on Tuesday).
"Emergencies Ministry servicemen scoured through the city districts, bridges and electrical cables, there was no damage," Gogoleva said.
The epicentre of the quake was about 150 km (93 miles) off Sochi in the Black Sea.
President Vladimir Putin ordered authorities to inspect Olympic sites, particularly those under construction, to ensure there was no damage, Interfax news agency reported.
Authorities said a explosion on a gas pipeline that feeds a a local power station occurred before the earthquake and was not related.
Gogoleva said the power plant had switched to fuel oil and the city was receiving electrical power. She said the reason for the blast was unknown.
Sochi, the first Russian city to host the Winter Olympics, is located near Russia's North Caucasus, which is plagued by violence linked to an Islamist insurgency.
(Reporting by Vladimir Soldatkin; Editing by Angus MacSwan)