Several jewish suspects were arrested on Sunday over an arson attack on June at a shrine where Christians believe Jesus performed the miracle of loaves and fishes,Israeli police said.
The arson had sparked widespread condemnation and concern from Christians globally, with the site visited by some 5,000 people daily, while also drawing renewed attention to religiously linked hate crimes in Israel.
"Several Jewish suspects have been arrested for the burning of the church and the Nazareth court has decided to extend their detention for the purposes of the investigation," police spokeswoman Luba Samri said in a statement of the overnight arrests.
Police did not provide a number or further details on their identities, but an ultra-nationalist organisation said three young Jewish men had been arrested.
Another police spokesman said the arrests followed an undercover investigation also involving the Shin Bet internal security agency.
The Church of the Multiplication at Tabgha, on the northwestern shore of the Sea of Galilee, is at the site where many Christians believe Jesus fed the 5,000 in the miracle of the five loaves and two fish.
One of the buildings within the compound was completely destroyed in the blaze but the church itself was not damaged.
Hebrew graffiti was found on another building within the complex, reading "Idols will be cast out" or destroyed. The text is part of a common Jewish prayer.
Religiously inspired hate crimes
A modern church currently sits at the site, incorporating remains of a 5th-century Byzantine church and its mosaics. The first building constructed there, a small chapel, is believed to have been built in the 4th century.
Versions of what Christians believe was Jesus's miracle are recounted in all four of the gospels of the New Testament of the Bible. The site is now owned by the German Roman Catholic Church.
Father Gregory Collins, head of the Saint Benedictine Order in Israel, which oversees the church, last month called the arson "an attack on Israeli democracy, not just on a religious group".
There has been a long line of attacks on Christian and Muslim holy places in both Israel and the West Bank in which the perpetrators are believed to have been Jewish extremists.
Tabgha was subjected to a previous attack in April 2014 in which church officials said a group of religious Jewish teenagers had damaged crosses and assaulted clergy.
In the immediate wake of last month's attack, police had detained 16 young Jewish settlers, but they were later released without charge after providing statements.
Ten of those initially detained were from Yitzhar, a Jewish settlement in the West Bank which is known as a bastion of extremists and where some residents have been involved in previous hate crimes.
In April, vandals smashed gravestones at a Maronite Christian cemetery near Israel's northern border with Lebanon.
That attack prompted President Reuven Rivlin to meet church leaders and pledge a crackdown on religiously inspired hate crime.