4 men arrested on suspicion of plotting UK terror attack Planning for the alleged plot was believed to be at an advanced stage.

 LONDON -- West Yorkshire police in England arrested four men early this morning on suspicion of plotting a terror attack, authorities said.

Planning for the alleged plot was believed to be at an advanced stage and connected to a Christmas target, a Yorkshire Police spokesman told ABC News today. The arrests followed searches in Sheffield and Chesterfield and searches in the area are ongoing, according to police.

The four men, ages 21 to 41, are being questioned at a police station in West Yorkshire after being detained in Sheffield and Chesterfield, police said.

The threat level for international terrorism in the U.K. was already "severe," meaning an attack is "highly likely."