Where is Abraham Grave?

And after this, Abraham buried Sarah his wife in the cave of the field of Machpelah before Mamre--the same is Hebron--in the land of Canaan.
(Genesis 23:19)

And Isaac and Ishmael his sons buried him in the cave of Machpelah, in the field of Ephron the son of Zohar the Hittite, which is before Mamre;the field which Abraham purchased of the children of Heth; there was Abraham buried, and Sarah his wife.
(Genesis 25:9-10)

According to the Jewish tradition Abraham Grave is in Hebron.

Muslim also believe that Abraham grave is in Hebron:

Habra (Hebron) is the village of Abraham al-Khalil (the Friend of God)...Within it is a strong fortress...being of enormous squared stones. In the middle of this stands a dome of stone, built in Islamic times, over the sepulchre of Abraham. The tomb of Isaac lies forward, in the main building of the mosque, the tomb of Jacob to the rear; facing each prophet lies his wife.
(Al-Muqaddasi http://commons.wikimedia.org/wiki/File:Strange.309.jpg )

But what is the Islamic source for that?

I asked in Islam community (source: http://www.orkut.com/Main#CommMsgs.aspx?cmm=3126&tid=2554556273932877972)
where is Abraham grave and what is the source for that.

At the beginning - no one knew where is the place.One even suggested mecca...

After a while a guy named Arif said:

"The grave of Ibrahim (as) is located in the Ibrahimi mosque. The mosque is now divided in two in 1994. One part for Muslims and another for Jews community.

but no authentic source.. "

So Muslim can't find any Islamic source not in Quran or Hadith that say that Abraham grave is in Hebron!

So on what they base this believe?

Other guy named mYstiKaL SouL said:

"Muslim tradition in this respect is not independent. anything in the sources of the People of the Book which doesnot contradict Islamic sources can be accepted. "

So that means that the source of Islamic tradition that Abraham grave is in Hebron is actually the Jewish tradition!!!

One of the guys(which by now deleted his profile) said it's like Isra'iliyat:

The term isra'iliyyat usually refers to early literature of various types attributed by Muslim scholars to Jewish and Christian sources. Despite the continual and pervasive negative regard for isra'iliyyat, however, a massive amount of this material has been utilised by Muslim commentators throughout Islamic history.
(http://cat.inist.fr/?aModele=afficheN&cpsidt=13759409)