A senior Hamas official was reportedly killed in a strike Tuesday in Lebanon’s capital city, putting Israel on high alert should the conflict in the region widen.

According to local news channels, Israel carried out a bombing that killed Saleh al-Arouri, the deputy chief of the political bureau for the Palestinian militant group in Beirut. The Hamas official is the highest-ranked member killed in the ongoing war between Israel and the group in Gaza.

The State Department listed al-Arouri as a terrorist and offered a $5 million reward for information about him, according to The Associated Press.

Despite the win for Israel in taking out the official, Hamas leaders have been quickly supplanted in the past. There’s also the question of how the Israeli bombing in an area where Iran-backed Hezbollah is strong could affect current fighting along the Lebanese-Israeli border. 

Hezbollah leader Hassan Nasrallah had promised retaliation in the past for all forms of Israeli targeting of allied militant leaders in his country, the AP reported. However, Nasrallah has seemed reluctant thus far to escalate the fighting.

Israeli officials have not provided comment on the bombing that killed al-Arouri. However, military spokesman Rear Adm. Daniel Hagari said “we are on high readiness for any scenario.”

Hezbollah said the strike was “a serious attack on Lebanon, its people, its security, sovereignty and resistance,” per the AP.

“We affirm that this crime will never pass without response and punishment,” the group said.

The Associated Press contributed.