Israel says it has carried out airstrikes on around 100 Hezbollah rocket-launchers in Lebanon, as concerns mount over escalating tensions between the two sides.

Israeli forces said the launchers hit through Thursday night were ready for immediate use. They pledged to continue the attacks to degrade Hezbollah's capabilities.

Hezbollah also said the group launched 17 attacks on Israeli military targets on Thursday.

The Lebanon-based Shia Muslim group has vowed retaliation after blaming Israel for the mass explosions of pagers and walkie-talkies earlier this week.

Hezbollah leader Hassan Nasrallah said in a speech on Thursday that "the enemy" has crossed "red lines."

Lebanon's health ministry says 37 people were killed and about 3,000 were wounded when the mobile devices exploded on Tuesday and Wednesday.

The United States, Britain and France have urged both Israel and Hezbollah to exercise restraint. The White House press secretary said that a diplomatic resolution is still achievable and urgently needed.