Gunmen briefly surrounded the EU's offices in Gaza, demanding an apology for the publication of cartoons of the Prophet Muhammad in European papers.
Gunmen also stormed the EU's offices on Monday
Members of Islamic Jihad and the Yasser Arafat Brigades fired into the air and climbed the compound's walls.
The gunmen left the offices after 45 minutes. There were no injuries.
Some Muslim countries have withdrawn their ambassadors to Denmark and boycotted Danish products after a paper there first printed the cartoons.
Other European journals reprinted the images on Wednesday to show support for free speech.
30 Sept: Danish paper Jyllands-Posten publishes cartoons
20 Oct: Muslim ambassadors in Denmark complain to Danish PM
10 Jan: Norwegian publication reprints cartoons
26 Jan: Saudi Arabia recalls its ambassador
30 Jan: Gunmen raid EU's Gaza office demanding apology
31 Jan: Danish paper apologises
1 Feb: Papers in France, Germany, Italy and Spain reprint cartoons
Some of the cartoons depict Muhammad as a terrorist. One image depicts the prophet wearing a turban shaped as a bomb with a burning fuse.
Islam bans any depiction of Muhammad or Allah, in case they lead to idolatry.
The cartoons have sparked protests, flag burning and calls for boycotts across the Islamic world.
Correspondents say armed protests such as Thursday's are common in Gaza.
On Monday, about 15 gunmen burst into the same EU offices and warned citizens of Denmark and Norway, where a newspaper reignited the row earlier this month, not to enter Gaza until an apology was made.
The Norwegian government, however, has taken the threats from Palestinian militant groups seriously and it announced on Thursday that its mission in the West Bank had been closed to the public temporarily.
"We have decided to close our mission in al-Ram to the public for the time being as we consider the security situation," Norwegian Foreign Ministry spokesman Rune Bjaastad said.