Israeli police blasted crowds with water cannons and made dozens of arrests on Sunday as thousands of protesters demanding a deal to free hostages in Gaza aimed to shut down the country with a one-day strike that blocked roads and closed businesses.

Groups representing families of hostages organized the demonstrations as frustration grows in Israel over plans for a new military offensive in some of Gaza’s most populated areas, which many fear could further endanger the remaining hostages. Fifty hostages remain, and 20 of them are believed to still be alive.

“We don’t win a war over the bodies of hostages,” protesters chanted in one of the largest and fiercest protests in 22 months of war. Even some former Israeli army and intelligence chiefs now call for a deal to end the fighting.

Protesters gathered at dozens of places including outside politicians’ homes, military headquarters and on major highways. They blocked lanes and lit bonfires. Some restaurants and theaters closed in solidarity. Police said they arrested 38 people.

“The only way to bring (hostages) back is through a deal, all at once, without games,” former hostage Arbel Yehoud said at a demonstration in Tel Aviv. Her boyfriend Ariel Cunio is still being held by Hamas.