Israel Gaza: Four Israeli soldiers injured in border blast
Four Israeli soldiers have been hurt, two of them seriously, in an explosion near the Israeli-Gaza border.
The army said a Palestinian flag was flying in the area, and when the troops approached they were hit by the blast.
Israel conducted air strikes on Hamas targets in Gaza in response. Separately, two Palestinian teenagers were killed by Israeli tank fire east of Rafah.
The pair approached the border in a suspicious manner, Israel's army said.
Israel and Hamas militants, who dominate Gaza, fought a war in 2014.
No group has so far said it was behind Saturday's explosion, which happened at 16:00 local time (14:00 GMT) east of the town of Khan Younis.
The army said the explosive device had been planted during a demonstration there on Friday and was attached to a flag.
The troops were approaching from the Israeli side when the device detonated.
Israeli Prime Minister Benjamin Netanyahu, who is attending a security conference in Munich, Germany, said: "The incident on the Gaza border is very serious. We will respond appropriately."
The Israeli army said it targeted 18 Hamas military targets from Saturday night through to Sunday, including "weapons manufacturing infrastructure" and a tunnel being dug by militants.
Palestinian officials said three Hamas training camps and one belonging to a smaller group had been struck.
Israeli media also said a rocket from Gaza hit a house in the south of the country on Saturday evening. There were no casualties
Israel holds Hamas responsible for all rocket and mortar fire from the territory. Hamas has fought three wars with Israel since 2008.
Correspondents say the border area has been generally quiet in the last few years but there has been an increase in violence since US President Donald Trump's announcement in December recognising Jerusalem as Israel's capital.
Israel regards Jerusalem as its indivisible capital. Palestinians want the east of the city, which Israel occupied in the 1967 Middle East war, to be a capital of a future state.
Correction 20 April 2018: An earlier version of this story wrongly stated that a rocket from Gaza landed near, rather than hit, a house in southern Israel.