"These are terrorist attacks that have only one goal: to kill people indiscriminately and arbitrarily and to spread fear," Chancellor Angela Merkel's spokesman Steffen Seibert told a government press conference.
Merkel's government stressed "Israel's right to self-defence against these attacks", he added.
Israel has launched hundreds of air strikes against the crowded costal enclave of Gaza, while Palestinian militants there have launched more than 1,800 rockets since Monday, the Israeli army says.
According to Gaza's health minister, 119 Palestinians have been killed in Gaza, including 31 children, while more than 830 have been wounded Gaza.
On the Israeli side, a woman in her 50s died late on Thursday after she fell while seeking shelter from rockets, according to the Sheba Medical Center.
This brings Israel's death toll to nine, including a child and a soldier.
On Tuesday, Euro-Mediterranean Human Rights Monitor described Israel's current actions in the Strip as "utterly appalling" and said it was "acting without respecting the principle of proportionality".
The most intense hostilities in seven years were triggered by Israeli aggression at Jerusalem's Al-Aqsa Mosque compound, the third holiest site in Islam.
Germany has seen scattered demonstrations this week over the escalating violence.
On Thursday, around 1,500 people gathered in the northern city of Bremen calling for "freedom for Palestine" in a protest which proceeded without incident, according to local police.
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However, some protesters have shouted anti-Semitic slogans and burnt Israeli flags.
Flags were burnt outside synagogues in Muenster and Bonn, with 16 people arrested.
On Wednesday evening, around 180 people shouted anti-Jewish slogans at a march in Gelsenkirchen, also in the west.
Seibert said Friday that Germany would not tolerate "anti-Semitic" demonstrations.
"Anyone who attacks a synagogue or defiles Jewish symbols shows that for them it is not about criticising a state or the policies of a government, but about aggression and hate towards a religion and the people who belong to it," he said.
German President Frank-Walter Steinmeier had on Thursday also condemned anti-Semitic protests.
"Those who burn Star of David flags in our streets and shout anti-Semitic slogans not only abuse the freedom to demonstrate, but are committing crimes," he told the popular Bild daily.
"Nothing justifies threats against Jews in Germany or attacks on synagogues in German towns," he said.
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