Hamas’s military wing and Islamic Jihad took responsibility on Monday for what they said was a suicide bombing in Tel Aviv late Sunday, and threatened further attacks because of the “continued civilian displacement and killings” of Palestinians.

The Israeli police and the Shin Bet security agency said in a statement that a “powerful explosive” had been detonated on Lechi Road in southern Tel Aviv, but made no mention of a suicide attack.

One passerby was moderately injured, the statement said, which described the bombing as a terrorist attack and said that the authorities were investigating. The statement did not say that the assailant had died.

If confirmed, it would be the first suicide bombing in Israel since around 2016.

The Israeli news media broadcast security camera footage of a man with a backpack in the area shortly before the blast. The man was killed in the explosion, news outlets said.

Peretz Amar, the police chief of the Tel Aviv District, said at a news conference that the attacker, who had no criminal record and had not been on the radar of the Israeli security authorities, entered Israel from the Israeli-occupied West Bank. Mr. Amar did not name the attacker but said the explosives had most likely been manufactured in the West Bank and were of low quality.

The attacker had most likely seen dozens of people gathered at a synagogue and stopped to prime the explosives, but had inadvertently detonated them, he said, adding that it could have been a large-scale attack had events turned out differently.