Six confirmed dead and 91 hurt but other reports claim hundreds killed as sources close to Hezbollah say Hassan Nasrallah is alive

• Middle East crisis – latest news updates

Israel has launched its heaviest air attack on Beirut in almost a year of conflict with the Lebanese militant group Hezbollah, levelling a number of buildings in a southern suburb in an apparent attempt to kill Hezbollah’s leader and a key ally of Iran, Hassan Nasrallah.

Six loud explosions were heard across the Lebanese capital late on Friday afternoon, and vast plumes of smoke were visible from as far as Batroun, a city an hour’s drive away.

Beachgoers say they are unafraid but in this one-time ‘capital of hostages’, Lebanon is now main talking point

Air raid sirens blared in Tel Aviv on Wednesday morning as, for the first time, Hezbollah fired a surface-to-surface missile at the coastal city. A few minutes after the incident, beachgoers flooded the bustling promenade, playing beach volley, cycling and kite surfing.

“Was there an attack this morning?” asked Eyal Kadosh, 31, confused, while resting on a bench with a friend after their daily workout. “Well, I’m here, what should happen will happen anyway.”

A land incursion would be a far more complex undertaking than the intelligence-led strikes pursued so far

No two wars are alike, even those fought between the same two combatants on the same terrain. But many of the challenges remain the same.

Israel’s most senior military commander has told troops that airstrikes will continue inside Lebanon as the Israeli military prepares for a possible ground operation. If its forces do cross the northern border they are likely to face obstacles they have seen before.