"He believes it's achievable," Press Secretary Karine Jean-Pierre told a briefing.

"The president continues to believe that we have to be optimistic and a diplomatic resolution is the best way."

Israel's army said it hit some 30 Hezbollah rocket launchers along with other "infrastructure" in air strikes carried out in Lebanon on Thursday.

"With the direction of IDF (military) intelligence, the IAF (air force) struck approximately 30 Hezbollah launchers and terrorist infrastructure sites, containing approximately 150 launcher barrels that were ready to fire projectiles toward Israeli territory," the military said in a statement.