This is the second vandalism incident at the site in recent days.
Adam Frank, the congregation's rabbi, told Ynet that he had passed by the sign at around 7 am, before the daily morning prayer, and at around 10 am – and it was clean. About 90 minutes later, police officers knocked on his door and informed him about the swastikas scrawled on the sign.
"We have been here for more than 40 years, we have no enemies and I have no idea who is responsible for this, but it's clear that these are Jews who are against the Conservative movement," Frank told Ynet. "The cross inside the Star of David aims to express their perception that our praying at the synagogue, wearing a skullcap and studying Torah are just external acts, and that inside we are evil."
The same sign, which is located on the corner of the busy Keren Hayesod and Agron streets, was destroyed only last weekend with graffiti reading "stinky Americans," alongside calls to remove the congregation from the area.
"This is a disgraceful act which must shock all the people of Israel," said the community rabbi. "The fact that someone can draw a swastika inside a Star of David on an Israeli synagogue means that we are no longer on the edge of a slippery slope. We are in a free fall. It's time for self-examination for those rabbis who preach anger and hatred instead of the love for the Jewish people."
The Masorti Movement said in a statement: "Yesterday it was a mosque – and today it's a synagogue."
Masorti Movement CEO Yizhar Hess added, "We are shocked. The serious graffiti at the Masorti synagogue in central Jerusalem, alongside the heartless writing, 'Go back to America!' with swastikas inside Stars of David, remind us once again of the slippery slope of hate crimes.
"Those who provided explicit or implied halachic justification for 'price tag' rioters yesterday gave justification for attacking liberal synagogues today."