JERUSALEM -- Militants in Syria fired several rockets into northern Israel on Thursday afternoon, prompting Israeli retaliatory fire, the military said -- the first time since the 1973 Mideast war that rockets from Syrian territory have slammed into Israel.

A total of four rockets exploded in an open field in the northern Galilee, where sirens warned residents of the incoming projectiles. The rockets sparked small fires but caused no injuries.

The military said it responded to the attack but did not elaborate. It said the rockets were fired by the Iran-backed Islamic Jihad group. There was no immediate claim of responsibility for the attack. Israel also said it holds the Syrian government responsible for attacks emanating from Syria. Sporadic mortar shells and gunfire have hit Israel on several occasions since the Syrian conflict broke out in 2011, but this was the first time rockets were used.

In southern Syria, an opposition activist said Israeli tanks fired at least four shells at Syrian army and pro-government positions. The activist, who goes by the name of Abu Omar al-Golani, said the shells hit near the Syrian town of Baath and the village of Khan Arnabeh.

Israel and Syria are bitter enemies, and Israel has avoided taking sides in the Syrian civil war, which pits President Bashar Assad's government against an array of militants, including the brutal Islamic State group, which has imposed a violent interpretation of Islamic law, or Shariah, on the parts of Syria and Iraq it now controls.

Still, Israel provides free medical treatment at Israeli hospitals for Syrians wounded in the fighting that reach its frontier.

Syria's conflict has also renewed tensions in the Golan Heights, a strategic plateau that Israel captured from Syria in the 1967 war. Despite constant hostility between the two countries Assad has been careful to keep the border mostly quiet since the 1973 war.

Israel has responded occasionally to attacks from Syria. It says some of the attacks have been accidental spillover from the conflict next door while others have been intentionally aimed at Israeli civilians and soldiers.

Associated Press writer Bassem Mroue contributed to this report from Beirut.