By Alexander Cornwell, Parisa Hafezi and Jeff Mason TEL AVIV/DUBAI/WASHINGTON (Reuters) -Iranian missiles struck major Israeli cities on Monday while Israel's prime minister said his country was on its way to eliminating "threats" from nuclear and missile facilities in Iran and civilian casualties mounted on both sides.

At least 24 people have been killed in Israel as Iran launched retaliatory airstrikes targeting civilian areas. A U.S. Embassy branch in Tel Aviv suffered minor damage.

Israel's military spokesman said that the country’s air force has destroyed 120, or about one-third, of Iran’s surface-to-surface missile launchers since the beginning of its confrontation with Iran.

A volley of missiles launched by Iran killed eight people and injured nearly 100 in Israel on Monday as the conflict between the two countries entered its fourth day.

The Iranian regime faces pressure as Israel strikes military targets, with Iranian Americans advocating for the overthrow of what one Iranian American describes as a "paper tiger regime."

Israel has no intention of deliberately harming the residents of Tehran, Israeli Defence Minister Israel Katz said, walking back earlier comments he had made on Monday.

In a small, tight-knit town near Haifa in northern Israel, residents here never thought they would experience such horror.

The Israeli military said that its air force has struck a number of command centers of Iran’s Islamic Revolutionary Guard Corps. It said that the command centers, which were in Tehran, were used to direct proxy groups to launch attacks against Israel.