Israeli attacks have killed 22 people in Gaza, the territory's civil defence agency has said.
Raising an earlier toll of 11, a spokesman for the agency said 12 people were killed in the north of Gaza, in the Gaza City area, while a further ten were killed in strikes in the south, around Khan Younis.
The attacks were on parts of the enclave under Hamas control since a ceasefire took effect in October, health authorities have said.
Medics said two people were killed in Shejaia suburb east of Gaza City and four in the nearby suburb of Zeitoun.
A third airstrike killed four Palestinians in Mawasi area, west of Khan Younis in the south of Gaza.
The Israeli military said its forces struck Hamas targets across Gaza after members of the Palestinian militant group fired on its troops.
No Israeli forces were injured.
Repeated shooting incidents have pointed to the fragility of the ceasefire.
Israel and Hamas have traded blame for what both call violations of the US-brokered ceasefire, the first stage of President Donald Trump's 20-point plan for a post-war Gaza.
Three of the attacks were far beyond an agreed-upon imaginary "yellow line" separating the areas under Israeli and Palestinian control, according to medics, witnesses and Palestinian media.
The Zeitoun attack was on a building belonging to Muslim religious authorities and the Khan Younis attack was on a UN-run club, both of which house displaced families.
The 10 October ceasefire in the two-year Gaza war has eased the conflict, enabling hundreds of thousands of Palestinians to return to Gaza's ruins.
Israel has pulled troops back from city positions, and aid flows have increased.
But violence has not completely halted.
Palestinian health authorities say Israeli forces have killed 290 people in strikes on Gaza since the truce, nearly half of them in one day last week when Israel retaliated for an attack on its troops.
Israel says three of its soldiers have been killed since the ceasefire began and it has targeted scores of fighters.
Israel steps up Lebanon attacks, killing at least one
Meanwhile, the Israeli military stepped up airstrikes in south Lebanon, killing at least one person as it pressed a campaign of near-daily attacks which it says is designed to block a military revival by Iran-backed Hezbollah in the border area.
On Wednesday, residents fled after Israel issued warnings on social media identifying buildings it planned to strike in four villages in the south, saying it was attacking Hezbollah military infrastructure.
Strikes on the villages of Deir Kifa, Chehour, Aainata and Tayr Filsay sent thick plumes of smoke into the air.
Earlier in the day, one person was killed in an Israeli strike in the southern village of Al-Tiri, the Lebanese health ministry said.
The Israeli military claimed it had killed a Hezbollah member who was working to "reestablish Hezbollah's readiness in the area".
Yesterday, Israel carried out one of its deadliest strikes in Lebanon since last year's war with Hezbollah, killing 13 people in a Palestinian refugee camp near the southern city of Sidon, the Lebanese health ministry said.
Netanyahu visit to Syria 'concerning' - UN chief
UN Secretary-General António Guterres called the "very public" visit by Israel's prime minister Benjamin Netanyahu to troops deployed in Syria in a buffer zone intended to separate the two countries "concerning."
"This very public visit is concerning to say the least. We call on Israel to respect the 1974 disengagement agreement," said Mr Guterres' spokesman Stéphane Dujarric.
Mr Netanyahu told Israeli troops deployed in Syria in the buffer zone that their presence was hugely important for safeguarding Israel.
When Syrian president Bashar al-Assad was ousted from power in December last year, Israel sent troops into the UN-patrolled buffer zone separating Israeli and Syrian forces on the Golan Heights since 1974.
Mr Netanyahu visited a military outpost in the buffer zone and spoke with troops as he inspected the site, in a visit slammed by Syria.
"We attach immense importance to our capability here - both defensive and offensive," Mr Netanyahu told soldiers, in a video released by his office.
He claimed they were "safeguarding the state of Israel and its northern border opposite the Golan Heights".
"This is a mission that can develop at any moment, but we are counting on you," he added.
Damascus called the visit "a new attempt to impose a fait accompli that contradicts relevant Security Council resolutions".
Syria "condemns in the strongest terms the illegal visit... considering it a serious violation of Syria's sovereignty and territorial integrity", the foreign ministry said in a statement.
"Syria reiterates its firm demand that the Israeli occupation withdraw from Syrian territory and affirms that all measures the occupation has taken in southern Syria are null and void and have no legal effect according to international law," it added.
