The annual Rapid Trident military exercises, taking place in the western Ukrainian village of Starychi until September 15, involve some 2,200 soldiers from 14 countries.

"(The participants) stand in solidarity with Ukraine, for Ukrainian security, Ukrainian sovereignty, and Ukrainian territorial integrity," the US Ambassador to Ukraine Marie Yovanovitch said at the opening ceremony.

The drills start a week before Russia holds its biggest military exercises since the Cold War, in the east of the country and with the participation of China and Mongolia.

A spokesman for the Ukrainian drills Taras Gren told AFP that some 350 pieces of military equipment will be used during the exercises.

The Ukrainian Border Guard Service and the National Guard troops will be involved for the first time, he said.

Hundreds of US soldiers have been training Ukrainian soldiers since 2015 to support them in their fight against Russian-backed rebels in the country's war-torn east.

On Monday, the Ukrainian army reported eight servicemen had been wounded over the past 24 hours in clashes with rebels although a fresh truce took effect last week.

More than 10,000 people have been killed since the rebel insurgency broke out in the eastern Donetsk and Lugansk regions in April 2014 following Russia's annexation of Crimea from Ukraine.

Ukraine and its Western allies accuse Russia of funnelling troops and arms across the border.

Moscow has denied the allegations despite evidence it has been involved in the fighting and its open political support for rebels.