KIEV, Jan. 9 (Xinhua) -- Seven people, including three children, were injured in a road accident in Ukraine's western Lviv Oblast on Monday, authorities said Tuesday.

The accident happened at about 1:00 p.m. local time (1100 GMT), when two passenger cars coming from opposite directions collided on a regional highway near the town of Sambir, the National Police of Ukraine said in a statement.

Four adults including both drivers, as well as three children aged five, nine and 10 years, were injured in the collision and taken to hospital.

An investigation is underway.

Starting from Jan. 1, Ukraine has tightened road safety regulations with harsher punishments for violations.