June 6 (Reuters) - Proxy advisory firm ISS on Friday

urged shareholders of Penn Entertainment ( PENN ) to elect all

three nominees of hedge fund HG Vora to its board ahead of the

casino operator's June 17 annual meeting.

ISS recommended that Penn's shareholders cast their votes

for HG Vora-nominated candidates William Clifford, Johnny

Hartnett and Carlos Ruisanchez.

"The company is facing sustained challenges, which have

resulted in total shareholder return and operational

underperformance," ISS said in a note.

Penn responded to ISS' recommendation by encouraging

shareholders to vote for Hartnett and Ruisanchez but opposed

Clifford's candidacy.

"Clifford demonstrated antiquated views of a rapidly

changing industry, and the same posture of resistance to

exploring value-generating solutions, which we believe would

hinder constructive decision-making," Penn Entertainment ( PENN ) said.

"PENN attempted multiple resolutions with HG Vora, but

all of our resolution attempts were rejected," the company said.

HG Vora said in April that it planned to push ahead with a

proxy fight at Penn to try and elect all three of its director

candidates after the casino operator said it would appoint only

two of them to its board.