A 24-year old man was arrested Friday on suspicion of inciting people to deliberately start fires, police said, bringing the number of suspects in custody to 12, a day after Prime Minister Benjamin Netanyahu vowed to treat those who are behind part of the wave of fires as “terrorists.”

The suspect, a Bedouin from southern Israel who allegedly posted messages on Facebook urging arson, was the first to be detained for incitement. Israeli Arab MKs called for his release, saying the post was sarcastic and had been misunderstood. Seen by The Times of Israel, the post concludes with a hashtag “Sarcasm, not serious.”

Police also arrested a second person Friday morning on suspicion of starting a blaze that destroyed at least 10 homes in the village of Beit Meir in the Jerusalem hills overnight. He was taken in for questioning, police said.

“We believe there are arsonists out there, but also weather conditions that allow this to spark [without human aid],” Jerusalem police chief Yoram Halevi told Army Radio after the first arrest

So far 12 people have been arrested for sparking or inciting at least some of the hundreds of fires that have threatened Israeli towns and forests this week.

Among them are six residents of the north, who the Shin Bet security agency and police believe are responsible for starting some of the devastating fires that ripped through Haifa on Thursday, causing the evacuation of 75,000 people and the destruction of hundreds of homes.

Troops from the IDF's Home Front Command assist in evacuations in Haifa in light of a massive fire in parts of the city on November 24, 2016. (IDF Spokesperson's Unit)

Troops from the IDF’s Home Front Command assist in evacuations in Haifa in light of a massive fire in parts of the city on November 24, 2016. (IDF Spokesperson’s Unit)

On Friday morning officials said that 600 homes had been damaged in Haifa, some 37 of them destroyed, and that some fires were still burning, but there were no longer any major conflagrations in the city.

Finance Minister Moshe Kahlon visited the stricken city and authorized officials to hand out cash advances to those who were left homeless and without money.

“About places to sleep, I told the mayor and other officials across the country, don’t look at the money and the bureaucracy, just work. Now we have to find solutions for the residents,” the Walla news site quoted him as saying.

The incitement suspect, a resident of the predominantly Bedouin town of Rahat in southern Israel, had posted messages on Facebook calling for further fire attacks, police said. He was to appear Friday in a Beersheba court.

The Ynet news site said he was the son of a prominent leader of the Islamic Movement and said his Facebook post had said “there are still forests where the fire has not reached, we need our crazy youths to do what is needed.” The report did not name him.

However, Arab lawmakers Ahmad Tibi and Ayman Odeh of the Joint (Arab) List party said the police misunderstood the Facebook post. The post, seen by The Times of Israel, was written in dramatic language, and the MKS said it was meant to be sarcastic derision of those actually doing the incitement. It calls for a boycott of Turkey for helping Israel to put out the fire, and for hooligans to make sure fires burn every forest in Israel. At the bottom of the post, the writer concludes with a hashtag “Sarcasm, not serious.”

The man arrested has a bachelor’s degree in economics, a master’s degree in communications and teaches photography to youths in his town.

Netanyahu on Thursday branded suspected arsonists and those who encourage them as “terrorists” and promised that harsh steps would be taken against them as the country struggled to deal with hundreds of brush fires, some of them apparently deliberately set.

“Every fire caused by arson, or by incitement to arson, is terrorism,” Netanyahu told reporters at a briefing in Haifa. “Anyone who tries to burn parts of the State of Israel will be punished severely.”

Meanwhile, many Arabic-speaking social media users in Israel and abroad have cheered on the fires, causing the Arabic-language hashtag label “Israel is burning” to reach the third-most trending tag on Twitter in several nearby Arab countries.

But Israeli security officials warned against jumping to conclusions about the cause of the wave of fires, saying the evidence for a widespread campaign of arson remains ambiguous.

Also Friday, MK Yael German from the Yesh Atid party appealed to Attorney General Avichai Mandelblit to take action against Rabbi Shmuel Eliyahu of Safed after he reportedly issued a religious ruling allowing people to shoot Arabs caught setting fires.

“Act immediately to end this racism and incitement,” she wrote.