(CNN) The Iran-backed Lebanese militant group Hezbollah has attacked an Israeli army base and a nearby military vehicle as tensions remain high along the border between Israel and Lebanon.

Israel says there were no casualties in the attack, and says it responded with artillery strikes on nearby Hezbollah positions, in the most serious single exchange across the border in more than four years.

The Israel Defense Forces have been on high alert in the north of the country for the past week after Hezbollah leader Hassan Nasrallah vowed revenge for several attacks on Hezbollah targets in Lebanon and Syria last weekend.

Shortly after 4 p.m. local time (9 a.m. ET) Sunday, the IDF says a Hezbollah squad fired anti-tank missiles at an Israeli battalion headquarters near the village of Avivim, hitting a building and a military ambulance but causing no casualties.

The IDF says it responded with around 100 artillery shells and "very limited" helicopter fire, targeting the area from where the missiles were fired, as well as other military sites.

Read More