Welcome to the NewsHour. The more than decade-old civil war in Syria appears to be reigniting as rebel fighters breached Aleppo, Syria's second largest city, following a surprise large-scale offensive this week.

It's the first time they've set foot there since they were ousted by a brutal military campaign eight years ago.

And it marks the most significant challenge to President Bashar al-Assad's government in years.

Videos released by the Syrian civil defense, or white helmets, showed the city and its surrounding villages in ruins.

Syrian government forces and their Russian allies have countered the insurgent in attacks in recent days with airstrikes.

The UN says at least 27 civilians, including eight children, have been killed in the fighting.

There are also simmering tensions elsewhere in the Middle East.

The fragile ceasefire between Israel and Lebanese Hezbollah militants

appears to be holding, but the Israeli military conducted another airstrike today

after it says it identified, quote, terrorist activity.

This video claims to show the destruction of a Hezbollah rocket launcher, and more footage

shows Israeli troops operating in southern Lebanon, where they can remain for up to 60 days.

A senior Israeli commander said their focus for now is enforcement and that they are watching

Hezbollah closely.

If Hezbollah make a mistake, it would be a big one.

We are prepared to return to offense and return to combat.

Yes, we are now in enforcement mode, but we can very clearly in a very short time

give the opposite order and move forward again.

The Lebanese army has accused Israel of breaking the ceasefire several times since it went into

effect. There have been no reported casualties in these Israeli strikes. Iran plans to expand

uranium enrichment at its two top nuclear sites,

sparking concern in the West that added enrichment capacity could bring more uranium up to weapons-grade levels.

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