LONDON, June 5 (Reuters) - European shares opened lower on Friday, setting a key regional index on course for its steepest weekly fall so far this year, after Greece delayed a key debt payment and as caution prevailed ahead of U.S. employment data.
The pan-European FTSEurofirst 300 index was down 0.6 percent at 1,548.10 points at 0705 GMT.
The index was down 4.3 percent since the start of the week, setting it on course for its steepest weekly loss since December amid a broad market rout which saw yields on German Bunds rise to eight-month highs on Thursday.
"I would stay short until there is more clarity on Greece," Mike Reuter, a trader at Tradition, said.
Economists polled by Reuters expect May's non-farm payrolls report, due at 1230 GMT, to show U.S. employers added 225,000 jobs in May, which would reinforce expectations of a rate hike as early as September. (Reporting By Francesco Canepa)