The moderate frontrunner in the race for Palestinian President called Israel the ‘‘Zionist enemy’’ on Tuesday after an Israeli tank killed seven Palestinian youths in a Gaza strawberry field.

Mahmoud Abbas’s use of language usually confined to militants drew swift condemnation from Israel, whose Army said it had targeted a mortar squad and expressed regret for any loss of innocent life.

Abbas, who is seeking to win over militants opposed to his calls for a ceasefire and peace talks over a Palestinian state, spoke in Gaza while campaigning for the Jan. 9 vote to pick a successor for Yasser Arafat.

Palestinian witnesses and medics in the northern Gaza village of Beit Lahiya said a tank shell landed and killed the young Palestinians aged 11-17 from two farming families. Fifteen other people were wounded, several critically.

Israel’s Army said it had targeted militants who had crept into the strawberry patch and fired mortar bombs into a nearby Jewish settlement, wounding two people. The Army commander in North Gaza expressed regret ‘‘if civilians were indeed hurt’’. The field, where the youths had been harvesting strawberries, was spattered with blood and body parts. Thousands of people joined a funeral march for the seven later on Tuesday.

Word of the incident angered Abbas, widely tipped to win the presidential election, as he continued campaigning in Gaza despite further fighting in the small coastal strip between Israeli forces and militants waging a four-year-old revolt.

‘‘We are praying for the souls of our martyrs who fell today to the shells of the Zionist enemy,’’ Abbas told a rally in the South Gaza refugee camp of Khan Younis. It was his first known use of a phrase favoured by radicals sworn to Israel’s destruction.