Relationship between Israel and Jordan

Some documents and sources claim that Israelis, especially Mossad played a fundamental but hidden role in killing Palestinian immigrants in Jordan, known as Black September. Like it is written:
“In the summer of 1970, in Oman, the capital of Jordan, a struggle started between Palestinian Fedayeen and the army units of Jordan. Leaders of some Arabian countries, plus Nasser, the president of Egypt, helped Malik Hussein and Palestinians to deal, but the conditions of the capital of Jordan was tense and chaotic. In the beginning of September, the International Union of Palestinian Students formed an international conference about the issue of Palestine in Oman. In that conference, there were suspicious people as well as the reputed and great social people who wanted to help Palestinians were coming to Oman. The suspicious people, who had Belgian, French and American passports and considered themselves a friend to Arabs, were indeed coming to weaken the Palestinian movement and to make their leaders stand against the United Republic of Arabs.”
They, intentionally attacked Nasser and Jordanian government. The streets of Oman in that days were like as if the streets were divided between Jordanian Soldiers and Palestinian Guerillas […]. [Progressively] the fight between Palestinian Fedayeen and the state forces of Jordan entered a new level […] in September 16 [1970] Malik Hussein and Palestinians signed a treaty to cease fire, but some hours later the fight started again. A big war inside Jordan was possible, and was to make the United States of America or Israel interfere. In September 21, in Washington DC, the issue of interfering of the United States of America was investigated. In this time, Nasser, the president of Egypt, wrote a letter to Brezhnev, secretary of communist party of USSR. According to this letter, USSR formed a statement and warned Imperialist countries not to interfere in the struggles between Palestinians and Jordanians.
In that time, when Arabs conference must have started its own work in Cairo, the capital of Egypt, Jordan’s arsenal started bombing Palestinian camps and sites in the center of Oman while kings and presidents of Arabian Republic were in Cairo. According to Palestinians information, in this attack almost 20 thousands of Palestinians died. Finally, the present representatives in Cairo agreed to send a political group to Oman and make both sides to cease fire. After all, in September 26, the treaty of cease fire was signed and Malik Hussein and Yasser Arafat were invited to the capital of Egypt, Cairo. So, Jamal Abdul Nasser, president of Egypt who is now dead, played the role of a go-between between Malik Hussein and Yasser Arafat and tried to dominate peace between them. Yet, the willfulness and obstinacy of Jordan’s king and Yasser Arafat made Nasser use all his influences and do all he could do to make the debates having a result. […]. In September 27, the final session of the conference was held. Malik Hussein and some of his men sat on one side of the table and Yasser Arafat and his men on the other side. Both sides tried to take control of their nerves, while they didn’t try to put away their guns. [Husnein] Hackle wrote in his memories that to Malik Faisal, the king of Kingdom of Saudi Arabia, it was told to take their guns. He irritated and answered: “no one can take their guns except foe Nasser.” After two hours of debating, the plan of treatment was finally planned. […] finally, the conference ended and the agreement between Malik Hussein and Yasser Arafat with the interference of Jamal Abdul Nasser was resulted.