EU foreign affairs chief Catherine Ashton said she was "concerned" by a fresh exchange of fire on Sunday in the Gaza Strip and southern Israel.
The exchange followed an earlier spike in violence which began when a rocket hit Israel on Wednesday and escalated sharply on Saturday with an Israeli air strike on Rafah. Nine Islamic Jihad militants and one Israeli died.
Then, on Sunday, a Palestinian was killed and another wounded in an Israeli raid on Gaza just hours after militants declared a ceasefire, according to medical sources.
"I am very concerned at the renewed exchange of fire.... I wholeheartedly condemn the indiscriminate targeting of civilians wherever they are. I call on all sides to respect the ceasefire brokered by Egypt," Ashton said in a statement.
Sunday's strike took place near the southern border city of Rafah and raised to 10 the number of Palestinians killed.
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