The same thing happened before the invasion of Afghanistan.
Before 9/11 there a huge build up of arms and troops in striking distance to afghanistan.
For the war in Afghanistan, huge transports of troops and material had to be organized well before the invasion. On November 7, 2000, the day all US-citizens were occupied with the election of their president, the UK announced its biggest military exercise since the Gulf War, operation Swift Sword (Saif Sareea in Arabic), involving 24,000 troops and a lot of heavy material.
The exercise took place in Oman, a strategic location, since all oil tankers from the Persian Gulf region (Saudi-Arabia, the United Arabic Emirates, Qatar, Kuwait, Iraq and Iran) have to cross the Gulf of Oman. Here the UK detaines a War Material Storage. They exercised on the coast of Oman from September 15 until the end of October 2001, and started moving their material in August 2001. The UK participated in the invasion.
From October 8 until the end of October, 2001 another military operation was planned in Egypt: NATO Operation Bright Star. It was the world's largest exercise with more than 11 Nations, and over 70,000 troops (among which 23,000 from the US) participating.
Among several other "coincidental" military moves towards Afghanistan, we notice that on July 23 2001 aircraft carrier Carl Vinson was sent out from Bremerton (on US West coast) to the Arabian Sea. It arrived just in time to launch the first air strikes on Afghanistan on October 7, 2001.