John Gill Commentary 2 Kings 24:10

"At that time the servants of Nebuchadnezzar king of Babylon came up to Jerusalem, and the city was besieged." — 2 Kings 24:10 (ASV)

At that time
When Jehoiachin reigned:

when the year was expired ;
so it is in (2 Chronicles 36:10) or at the revolution of the year; which some take to be autumn, the beginning of the civil year with the Jews; but rather it was the spring, the time when kings went out to battle, (2 Samuel 11:1)

the servants of Nebuchadnezzar king of Babylon came up against
Jerusalem ;
that is, his army, under proper generals and officers, and by his orders:

and the city was besieged ;
in form by the Chaldean army.