Albert Barnes Commentary Jeremiah 35:11

"But it came to pass, when Nebuchadrezzar king of Babylon came up into the land, that we said, Come, and let us go to Jerusalem for fear of the army of the Chaldeans, and for fear of the army of the Syrians; so we dwell at Jerusalem." — Jeremiah 35:11 (ASV)

The Syrians - The Septuagint substitutes Assyrians for Syrians, but marauding bands of the Aramaeans are probably meant.