The most common and most likely answer to this crossword clue is the 6 letter word SAIGON
I've seen this crossword clue in Financial Times
S
A
I
G
O
N
More clues leading to the result SAIGON
- I work in medical institution in old city
- Keep feeling tired after imbibing a single vintage port
- Number with US soldier when retreating in war-torn city
- Former capitalI left abruptly
- Old city disciple embraces a US soldier turning up
- A song I composed recalled city in Asia
- Foreign city journey — very good person will be around shortly
- City boy holding a US soldier up
- Song composed about top class city
- Capital making one a bargain invested in health resort?
Buddy explains!

The straight part
We know that "war-torn city" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case war-torn city = saigon.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.