The phrase "army clashed" is correct and usable in written English.
It can be used to describe a confrontation or conflict between military forces.
Example: "The two armies clashed on the battlefield, resulting in heavy casualties on both sides."
Alternatives: "military engaged" or "forces collided".
August 28, 2006: The Mahdi Army clashed with Iraqi soldiers in Diwaniya (28 killed, 70 wounded).
One soldier was killed in fighting further south where the army clashed with rebels near the border with Albania, it was reported.
In the last stage of the civil war, large parts of East Beirut and its Christian suburbs were destroyed or heavily damaged when the Lebanese army clashed with the LF.
Peacekeepers confirmed that the Sudanese Army clashed with rebel forces two times last week, and possibly three, part of a surge in violence since the rebels pulled out of peace talks in early May.
"The country is changing very fast, people are emigrating, and losing a beloved pope only makes it more difficult and confusing .Last October the Egyptian army clashed with a group of mostly Coptic protesters, killing 25 people.
JUBA, South Sudan South Sudanan's army clashed Sunday with ethnic Nuer fighters, and government officials accused rebels of mobilizing the force despite the government's offer of a truce to end the conflict.
Less than 40 miles away, the rival armies clashed at Gettysburg.
The Neapolitan and papal armies clashed at the Battle of Nocera.
In ancient times (as in our own) weapon-wielding robbers ambushed travelers, and tribal armies clashed over shifting frontiers.
The result was a series of mostly small-scale skirmishes in the vicinity of the Rappahannock, as advance elements of the two weakened armies clashed.
On July 3 , 1866 the two armies clashed in this struggle's only major Austro-Prussian battle, the Battle of Königgrätz, or Sadowa as it is known in Austrian histories.
