Officers from MPS Counter Terrorism Command (SO15), Kent police and the MPS Specialist Firearms Command (SCO19) stopped an outbound vehicle at Dover port at around 11.30pm on Sunday.
Police said a further 12 men and one woman who were stopped in the same vehicle were arrested on suspicion of immigration offences by Immigration Enforcement officers.
At around 3.45am today two men aged 24 and 40 were arrested in east London, while at 8.30am a man, 28, was arrested, all on suspicion of being concerned in the Commission, Preparation or Instigation of acts of Terrorism contrary to section 41 of the Terrorism Act 2000.
Five men have been arrested on suspicion of commission, preparation or instigation of acts of terrorism in Dover and east London, Scotland Yard said.
Three more men have been arrested today. The operation was "not in response to any immediate threat," police said.
Hassan is the fourth Portsmouth man killed fighting in Syria. His family want the government to make it easier for fighters to come home.Read the full story ›
School teacher Jamshed Javeed, 30, from Manchester, has pleaded guilty at Woolwich Crown Court to two Syria-related terrorism offences
British jihadists who go to fight in Iraq or Syria could be tried for treason if they return to the UK, the Foreign Secretary has suggested.Read the full story ›
The number of investigations into terror activity in the UK has risen sharply, Britain's counter-terrorism chief has warned.Read the full story ›
A man has been charged at Westminster Magistrates Court with a number of offences under the Terrorism Act, including making electronic copies of magazines entitled 'Ultimate Guide to USA Army Combat', '39 Ways to Serve and Participate in Jihad' and '44 Ways to Serve and Participate in Jihad'.
Swedish nation Bherlin Gildo, 36, was also charged with attending a place known to be used for terrorist training, and for receiving instruction in the use of firearms in connection with acts of terrorism.
He was remanded in custody to appear the the Old Bailey on October 27.
A British militant, fighting with Islamic State in Iraq, has claimed he would be 'honoured' to murder a western captive.
He also says he is prepared to return to the UK to spread terror here.
ITV News Political Correspondent Romilly Weeks reports:
Investor confidence "has been hurt" by terrorist attacks carried out in emerging economies rich in natural resources, an expert has warned.
Jordan Perry, a principal political risk analyst at Maplecroft, said:
Libya, Kenya and Egypt are among a handful of countries to witness a significant increase in risk...and investor confidence in key sectors, including tourism and oil and gas, has been hurt.
When faced with rising security costs and decreasing safety for their personnel, companies can, and do, reconsider their country-level commitments.
China, Egypt, Kenya and Libya are most likely to experience significant increases in terrorist attacks, according to risk experts.
Maplecroft's Terrorism and Security Dashboard found:
- Twelve countries are classed as "extreme risk"; Iraq topped the list, followed by Afghanistan, Pakistan, Somalia, Yemen, Syria, Lebanon and Libya.
- It also includes the growth economies of Nigeria, the Philippines, Colombia and Kenya.
- Iraq, rated as the highest risk country, recorded more than three times as many acts of terrorism as Pakistan with 3,158 attacks resulting in 5,929 deaths - an increase of 2,188 on the previous year.
- In Nigeria, the campaign of violence by Islamic militant group Boko Haram saw the country record the highest number of fatalities per attack, resulting in 3,477 killed - an average of 24 people killed per attack, compared to two deaths per attack in Iraq.