Police arrested three people Sunday morning on suspicion of being connected with the incident.
“The arrested individuals are suspected of attempted arson,” Peter Nordengard, duty officer with Police Region Väst (West), told TT.
No injuries are reported following the attack and the synagogue was not damaged.
“There was a strong fire in the yard, but then it rained and the flames went out quickly,” Allan Stutzinsky, a spokesperson for the Jewish Community in Gothenburg (Judiska församlingen i Göteborg), told TT.
Police received reports of the attack shortly after 10pm on Saturday.
A community centre connected to the synagogue was open for a youth event with around 20-30 attendees at the time of the incident.
A mother of one of the children attending said that guards are normally deployed for events at the centre.
“They ordered the young people to run down to the basement. They are there now. My daughter says that it smells of gasoline. It is very unpleasant. We’ve been worried that something like this could happen,” the mother told newspaper GT on Saturday night.
“I received an SMS from her 20-30 minutes ago. She wrote ‘Mum, I’m starting to get scared’, and that 20 masked men were throwing burning objects,” she said.
Although the motive for the attack is unknown, it follows anti-Semitic incidents in both Malmö and Stockholm earlier this weekend.
Demonstrations in both cities took place in reaction to US president Donald Trump's decision to move the American embassy from Tel Aviv to Jerusalem and recognise the latter city as the Israeli capital.
Willy Silberstein, former chairperson with the Swedish Committee against Anti-Semitism, told Expressen TV that the series of incidents could be related to Trump’s announcement.
“When the USA decides to move the embassy to Jerusalem, that results, in the sick world we live in, in consequences for Jews living in Sweden. Swedish citizens become part of the conflict,” Silberstein said.
Sweden’s foreign minister Margot Wallström called the threats “completely unacceptable” in a message posted on Facebook.
In a written statement to TT, Prime Minister Stefan Löfven condemned the anti-Semitic incidents.
“I am terribly upset by the attack on the synagogue in Gothenburg yesterday, and that violence against Jews was incited at a demonstration in Malmö. There is no place for anti-Semitism in Swedish society. Those behind it must be made responsible. All democratic forces must now work together for a tolerant and open society where everyone feels safe,” Löfven wrote.