Israel hit targets in Gaza, after rocket is fired
"An army attack helicopter targeted a Hamas military position in the south of the Gaza Strip," an army statement said.
It said it had responded after a "launch towards Israel", claimed to be a rocket.
Hamas said the Israeli attack helicopter fired two missiles which damaged one of their positions but caused no casualties.
It was the first rocket to be fired from Gaza since an Egyptian-brokered ceasefire announced on 13 November ended the worst flare-up around the territory since a 2014 war.
Hundreds of rockets and mortar rounds were used in the barrage, killing one person and wounding 27 in Israel over a 48 hours period.
It followed a botched Israeli commando raid, which left a Hamas commander, six Hamas members, and an Israeli officer dead.
Seven Gazans were killed and 26 wounded in a wave of Israeli air strikes on the besieged land strip, before a ceasefire was agreed.
Israeli troops have also opened fire on mass demonstrations along the Gaza border since 30 March, leaving hundreds of unarmed Palestinian protesters, medical workers and journalists dead or disabled.
During a protest on Friday, Israel troops shot dead Karam Fayyad, 26, on the border east of the city of Khan Younis, the Gaza health ministry said.
Israeli snipers, air strikes and artillery have hit the land strip over the past decade, which is besieged by the Palestinian and Egyptian militaries, leaving to shortages of vital food, medical supplies and building materials.
Israel and Palestinian militants in Gaza have fought three wars since 2008.