Wasn't the Roman army the abomination which caused desolation, and the holy place (where the abomination ought not to stand) Jerusalem?
This reading certainly makes these scriptures consistent with each other.
Matthew 24:15-22 “Therefore when you see the ‘abomination of desolation,’ spoken of by Daniel the prophet, standing in the holy place” (whoever reads, let him understand), “then let those who are in Judea flee to the mountains. Let him who is on the housetop not go down to take anything out of his house. And let him who is in the field not go back to get his clothes. But woe to those who are pregnant and to those who are nursing babies in those days! And pray that your flight may not be in winter or on the Sabbath. For then there will be great tribulation, such as has not been since the beginning of the world until this time, no, nor ever shall be. And unless those days were shortened, no flesh would be saved; but for the elect’s sake those days will be shortened.
Mark 13:14-20 “So when you see the ‘abomination of desolation,’ spoken of by Daniel the prophet, standing where it ought not” (let the reader understand), “then let those who are in Judea flee to the mountains. Let him who is on the housetop not go down into the house, nor enter to take anything out of his house. And let him who is in the field not go back to get his clothes. But woe to those who are pregnant and to those who are nursing babies in those days! And pray that your flight may not be in winter. For in those days there will be tribulation, such as has not been since the beginning of the creation which God created until this time, nor ever shall be. And unless the Lord had shortened those days, no flesh would be saved; but for the elect’s sake, whom He chose, He shortened the days.
Luke 21:20-24
“But when you see Jerusalem surrounded by armies, then know that its desolation is near. Then let those who are in Judea flee to the mountains, let those who are in the midst of her depart, and let not those who are in the country enter her. For these are the days of vengeance, that all things which are written may be fulfilled. But woe to those who are pregnant and to those who are nursing babies in those days! For there will be great distress in the land and wrath upon this people. And they will fall by the edge of the sword, and be led away captive into all nations. And Jerusalem will be trampled by Gentiles until the times of the Gentiles are fulfilled.