Police arrested four men on terror charges as part of an ongoing international anti-terrorism operation, police said Tuesday.

Anti-terrorist forces working with West Yorkshire police arrested a 29-year-old man and two 21-year-old men in east London. A fourth man, who is 28 years old, was arrested in southeast London.

All four men were arrested on suspicion of the commission, preparation or instigation of acts of terrorism and were being held in a central London police station, the Metropolitan Police said.

CountryWatch: United Kingdom

Authorities said the arrests were related to an ongoing operation into alleged international terrorism being led by West Yorkshire Police, in which two people have been charged.

West Yorkshire police arrested a 21-year-old man at Manchester Airport on June 6, and detained a 16-year-old the following day. They were charged last week with conspiracy to murder "person or persons unknown," and with conspiracy to cause a public nuisance by use of poisons or explosives to cause disruption, fear or injury.

Aabid Hussain Khan, 21, also was charged under the Terrorism Act with possessing "an article, namely a computer hard drive and contents, in circumstances which gave rise to the suspicion that his possession was for a purpose connected with the commission, preparation or instigation of an act of terrorism."