At least 414 people were killed and almost 6,500 others injured after a 7.3-magnitude earthquake struck near Iran's border with Iraq, authorities said Monday.

Rescuers were trying to find survivors trapped under collapsed buildings but their efforts were hindered in many places by landslides. More than 100 aftershocks were registered, according to Iranian officials.

Many houses in rural areas of Iran are made of mud bricks that can crumble easily in a quake.

Iranian authorities said the quake killed 407 people with at least 5,953 were injured. Iraq's Interior Ministry confirmed that seven people in the neighboring country were killed by the quake, with 535 people wounded.