The two nations have massed a million troops along their mutual border.
Every week for the past year, Palestinians have massed at the fence to demonstrate in the March of Return.
Turkish tanks and troops have massed in the border region, and Erdogan has said an invasion could occur this week.
Another is south of Kunduz in the direction of Kabul, where 800 to 1,000 fighters have massed.
Some 80,000 civilians have massed in nearby Gereida, fleeing fighting between government forces, rebels and janjaweed militants.
At present, about 20 American ships have massed off Japan's northeastern coast, including the Ronald Reagan, a nuclear-powered carrier whose helicopters are busily ferrying supplies to survivors.
Certainly thousands of Turkish troops, backed by tanks and artillery, have massed for a possible offensive against Kurdish PKK rebels in Iraq.
The air strike came 24 hours after the Israeli Army was reported to have massed troops and armor along Lebanon's southern border.
Tens of thousands of people have massed outside the army headquarters since 6 April, initially to urge the armed forces to back their demand that Bashir be removed.
May is expected to highlight the threat posed by dispersing Isis fighters, some of whom have massed near the north of Jordan.
Thousands of migrants from Central America have massed along the border of Mexico and the United States — with thousands more on the way.
