People in Londonderry and Strabane have been asked to be vigilant after a police received a bomb warning.
At about 1030 BST on Thursday, somebody called police and said "there's a bomb at the Brae".
Police have checked locations known to them that match the name given, but nothing has been found.
In Dungannon at about 1520 BST, police were warned about a bomb at Coalisland Road. They are searching the area, but nothing has been found.
Police are now advising people living close to both locations to be watchful and to report anything suspicious.