Iran's Islamic Revolutionary Guard Corps (IRGC) has threatened a military response if attacks on Lebanon are not "immediately stopped." This was stated in a statement distributed by Iranian state media, UNN reports with reference to NYT.
The IRGC statement notes that retaliatory measures will be directed against "aggressors in the region," presumably referring to Israel.
Let's add
US President Donald Trump today called Israeli strikes on Lebanon "a separate clash" with "Hezbollah" that "was not included" in the two-week ceasefire agreement.
According to Fars news, Iran announced a ban on oil tankers passing through the Strait of Hormuz after the Israeli attack on Lebanon.
Recall
On the night of April 8, US President Donald Trump announced a two-week suspension of attacks on Iran.
Iran and Israel, following the US, agreed to a two-week ceasefire.