A total of 25 people have been killed in new attacks by the Israeli army in the Gaza Strip despite the current ceasefire, the Hamas-controlled health authority said on Wednesday.

The announcement came after the Israeli Defense Forces (IDF) said it had targeted Hamas positions across Gaza in response to several "terrorists" opening fire on an area in Khan Younis where Israeli soldiers were deployed.

"This action constitutes a violation of the ceasefire agreement," the IDF said, adding that no Israeli troops were injured.

Khan Younis is the largest city in the southern Gaza Strip.

The Palestinian news agency WAFA reported that 10 people were killed and dozens wounded in an Israeli strike on a building used by a Hamas-controlled authority in Gaza City, in the north. Three minors were among the dead, according to the report.

The health authority said more than 70 people were injured in the latest attacks.

Residents told dpa on Wednesday evening that no further strikes were occurring at that time.

Violent incidents have been reported repeatedly since the ceasefire began on October 10.