Israel has been stepping up attacks against the Shia Muslim group Hezbollah in Lebanon. Hezbollah is vowing to strike back, saying that they used newly developed drones for the first time in their attacks on Sunday against a military base in northern Israel.

The Israeli military announced on Tuesday that it had struck more than 200 Hezbollah targets in southern Lebanon and deep within the country, including the group's cells and anti-tank missile posts.

Lebanese health ministry officials said on Monday that 21 people had been killed in an Israeli air strike on the town of Ayto, northern Lebanon.

Lebanon's state-run news agency says the death toll in the country has reached 2,309 since the ongoing fighting began.

Local media say Ayto is a predominantly Christian area. No information is available about its relations with the Shia organization Hezbollah. The Israeli military has not yet explained their aims for the air strike.

In Israel, Hezbollah's drone attacks on a military base on Sunday night killed four Israeli soldiers and wounded about 60 others.

Israeli Prime Minister Benjamin Netanyahu visited the base on Monday. He said, "We will continue to strike Hezbollah without mercy everywhere in Lebanon -- including Beirut."

Hezbollah, for its part, said in a statement on Sunday that it had launched not only missiles toward various targets but also a large number of drones, including some used for the first time.

It said the advanced drones penetrated Israeli "air defense radars without detection and reached their targets."

Hezbollah warned of further counterattacks if Israel "continues its aggression."