* Russia has agreed three-month extension of price discount
* Sefcovic seeks deal until Stockholm arbitration (Adds details, background)
BRUSSELS, May 5 (Reuters) - European Commission Vice President Maros Sefcovic aims to conclude talks with Ukraine and Russia by the summer to ensure security of gas supply for next winter and beyond, he said on Tuesday.
Summer in Brussels is considered to begin when the European institutions take holiday in August.
Ukraine, the transit route for around half of the gas Russia pumps to the European Union, has been locked in a pricing dispute with Gazprom that resulted in a supply cut-off to Kiev last year.
Commission-brokered talks secured a temporary deal, but Sefcovic wants to extend that until arbitration in Stockholm can agree a permanent solution, which is expected to take until late 2016.
“I hope to have the chance to conclude by the summer,” Sefcovic said in Brussels, referring to talks brokered by the European Commission between Ukraine and Russia.
The Commission is keen to prolong a winter package negotiated late last year by former Energy Commissioner Guenther Oettinger.
Russia agreed to extend gas price discounts for Ukraine from April 1 for three months.
Sefcovic had said he hoped for more three-way political talks in April, but they they did not take place.
Ukraine, meanwhile, is seeking to reform its outdated and inefficient energy infrastructure as part of EU conditions for support.
Sefcovic, who has just visited Ukraine, said his message to the nation was: “You keep reforming and we’ll keep supporting you.” (Reporting by Barbara Lewis; editing by Robert-Jan Bartunek and William Hardy)