Negotiating with Israel 'unforgivable mistake': Khamenei
The de facto Saudi leader's comments were widely seen as a futher sign of thawing relations between the kingdom and Israel.
Both countries are major US allies and are arch-rivals of Iran. Riyadh is currently facing off against Tehran in a regional power struggle - the two states back competing factions in Syria, Iraq, Yemen and elsewhere.
"Movement toward negotiation with the cheating, lying and oppressive regime (of Israel) is a big, unforgivable mistake that will push back the victory of the people of Palestine," Khamenei said in a official statement.
Prince Mohammad's comments generated considerable controversy as Israel has in recent days shot and killed unarmed Palestinians protesting along the Gaza-Israel border.
After the crown prince's comments, his father King Salman reiterated Saudi Arabia's support for Palestine.
In November, leaked reports also emerged that Riyadh and Tel Aviv maintain covert contact despite no official diplomatic ties.
Khamenei made the remarks on Wednesday after receiving a letter from Hamas leader Ismail Haniya, who criticised Arab states for supporting the US.
Hamas runs the Gaza Strip, where at least 17 Palestinians were killed by Israeli forces during Land Day demonstrations last week.
Agencies contributed to this report.
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