* Islamist demonstrators cheer Hamas militants, urge more rocket attacks on Israeli cities
* Muslim Brotherhood leader slams Arab leaders for failing to intervene
By Suleiman Al-Khalidi
AMMAN, July 20 (Reuters) - Hundreds of mainly Islamist Jordanian protesters burnt Israeli flags in Amman on Sunday as demonstrators called on Palestinian Hamas militants to step up rocket attacks against Israeli towns and cities to avenge civilian deaths caused by Israel's offensive in Gaza.
Demonstrators near the Israeli embassy in Amman's affluent Rabia district chanted "Death to Israel" in one of the biggest public outpourings of anger against Israel in the last few years.
More than 60 Palestinians and 13 Israeli soldiers were killed on Sunday as Israel shelled a Gaza neighbourhood and battled militants in the bloodiest fighting in a near two-week-old offensive that has led so far to a death toll of over 400 Palestinians, most of them civilians.
Hundreds of mosques in Jordan held prayers for those killed, and protesters chanting slogans backing Hamas urged a jihad (holy struggle) in smaller marches in Amman and in cities and refugee camps across the kingdom.
"O Hamas... Your rockets have raised our heads... hit again and again Ashkelon and Tel Aviv," angry youths carrying a large Palestinian flag shouted.
"O Hamas, you are the gun and we are your bullets," chanted a dozen bearded Islamist youths wearing green headbands of the Qassam Brigades, the armed wing of Hamas.
Most of Jordan's seven million citizens are of Palestinian origin, they or their parents having been expelled or fled to Jordan in the fighting that accompanied the creation of Israel in 1948.
Hamas has a large following among nearly two million U.N. registered Palestinian refugees living in refugee camps across the kingdom, which hosts the largest number of Palestinian refugees.
Sheikh Hammam Saed, the head of Jordan's Muslim Brotherhood, the country's largest political party and a bastion of opposition to the kingdom's pro-Western policies, lambasted Arab leaders for failing to lend support to Hamas.
The Islamist leader also slammed Egyptian President Abdel Fattah al-Sisi, for whom Hamas is a security threat because it is an offshoot of the Muslim Brotherhood, for effectively closing the border crossing with Gaza. He said hampering the entry of essential aid was inhumane and leading to the suffering of thousands of civilians.
"These Arab regimes have made us accustomed to taste the bitterness of defeat and now the day has come that someone (Hamas) has ended this humiliation and weakness by their heroic resistance," Saed told the protesters.
Demonstrators also saluted Turkey's Prime Minister Tayyip Erdogan, a vocal supporter of Hamas, who has ratcheted up his rhetoric against Israel and criticised the United States and the rest of the world for failing to intervene.
Hundreds of protesters, who were prevented by a heavy cordon of riot police from approaching the building, also demanded the government shut the Israeli embassy and scrap Jordan's peace treaty with the Jewish state.
Jordan is one of only two Arab states to have formally ended hostilities with Israel. But this has never won much domestic favour, given Israel's continued occupation of the neighbouring West Bank. (Reporting by Suleiman Al-Khalidi; Editing by Dan Grebler)