For the king of the North will muster another army, larger than the first; and after several years, he will advance with a huge army fully equipped (Dan 11:13).

The King of the North represents the nations of the West led by the United States. They will come with an army even larger than the one that invaded Iraq.

This war will occur several years after the war in Iraq, when the United States has mostly withdrawn from Iraq. The expression "several years" is literally "the end of the times". This means that the invasion takes place at the end of the Times of the Gentiles. An uprising will occur first, as the presence of a foreign army in Iraq stirs up the Middle East.

Daniel does not say which nation will be invaded. Iraq has borders with Saudi Arabia, Jordan, Syria and Iran, so victory over Iraq has given the United States and its allies the ability to attack any of these nations. This is unlikely to be Iran as the large horn of the Goat has already smashed two horns off the Ram (Dan 8:7,8).

I believe it is more likely that that Daniel is describing an Invasion of Saudi Arabia. It has become one of the most unstable nations in the Middle East. The Saudi royal family is corrupt, immoral and dysfunctional. King Fahd is incapacitated and many princes are vying for power. While the royal family is extremely rich, the rest of the population is very poor. 

Most the population is young, with being under the age of eighteen. They have been educated in schools dominated by Wahhabi clerics. The schools are breeding ground for militant Islam and preachers all over Iraq openly call for jihad against the west. Saudi Arabia is a powder keg that just needs a match to set it alight.

I believe that Daniel saw a rebellion against one of the rulers of Saudi Arabia.

In those times many will rise against the king of the South (Dan 11:14).

Saudi Arabia is directly to the south of Israel. It is the heart of the Middle East because Mecca is the spiritual home of Islam.

Daniel says that people will rise up against the government that controls Saudi Arabia. This rebellion will threaten to disrupt oil supplies to the West. The United States is very dependent on this unstable nation. Saudi Arabia holds a quarter of the world’s oil reserves. It has enormous surplus oil production that allows it to determine the price of oil throughout the world. 

The Saudis have deposited trillions of dollars in American banks and own enormous shareholdings in American companies. The collapse of the Saudi royal family would be a disaster for the United States and Europe.  (It may  cause a world wide economic disaster).  They will invade to Saudi Arabia to protect their economies (Dan 11:13).

The western invasion force will be very successful.

Then the king of the North will come and build up siege ramps and will capture a fortified city. The forces of the South will be powerless to resist; even their best troops will not have the strength to stand (Dan 11:15).

The invading army will capture a strategic city (probably where the rebellion has occurred or a religious city like Mecca). Even the best troops in the invaded nation will be powerless to stand. Saudi Arabia has one of the best equipped armies in the world, but it will powerless against the United States juggernaut.

There is a prophecy about the destruction of Arabia in Isaiah 21:13-17. The people will be forced to hide in the desserts and caves from the invading army.

From the face of destruction they fled, from the face of a stretched-out sword, and from the face of a trodden bow, and from the face of the grievousness of battle (Is 21:15 YLT).

The repetition of the word sword signifies (stretched-out sword) the intensity of the attack. Note the reference to "destruction" and the "grievousness of battle". This suggests that the King of the North may use "weapons of mass destruction" to achieve victory.

Bowmen symbolise the Islamic revival (see Islam Advances). Isaiah saw the bow being trampled. This suggests that the Islamic revival in Saudi Arabia will be crushed so that only a remnant remains.

The survivors of the bowmen, the warriors of Kedar, will be few.  The Lord, the God of Israel, has spoken (Is 21:16).