Rockets are launched from Gaza Strip to Israel. Israel killed a senior Islamic Jihad commander in Gaza early Tuesday in a resumption of pinpointed targeting that threatens a fierce round of cross-border violence with Palestinian militants. Picture: Hatem Moussa/AP

Tel Aviv - Militants fired rockets towards Israel from the Gaza Strip early Wednesday, one day after the Palestinian group Islamic Jihad called the killing of its leader by Israel "a declaration of war."

The Israeli military sent aircraft to target the squad responsible for the "heavy barrage" of rockets and said that "a hit was identified."

Two people were killed in Israeli airstrikes, the Health Ministry in Gaza said on Wednesday, raising the death toll since the escalation in violence began to 12.

One of the worst rounds of Israeli-Gaza violence in five years began in response to news that Israel had targeted two senior Islamic Jihad leaders.  

Baha Abu al-Ata, the 42-year-old leader of the Quds Brigades, which is the armed wing of the Islamic Jihad in the Gaza Strip, was killed alongside his wife in an aerial attack on their house on Tuesday.

Three Israeli rocket attacks west of the Syrian capital Damascus targeted the house of Akram al-Ajouri, who dpa sources said is another leader of the Quds Brigades.

Syrian state-run news agency SANA reported that the militant had not been killed in the attacks, but that his son, Mouaz, and another person were dead, and 10 other people were injured.

Islamic Jihad is one of the most powerful militant groups in the Gaza Strip and has gained influence since 2014 with the help of financial backing from Iran.

The Israeli army said that more than 200 rockets have since been fired from Gaza, dozens of which were intercepted by the country's Iron Dome aerial defence system.

Warning sirens continued to blare on Wednesday morning in several towns across southern Israel. 

Israel's Magen David Adom (MDA) ambulance service said late Tuesday that it had treated 46 people for injuries related to the rockets.

According to Israeli media reports, Egypt and the United Nations are negotiating intensely behind closed doors to de-escalate the situation.