Two men suspected of having terrorist links were arrested early Thursday by police in London, following raids conducted by Scotland Yard. Earlier this week, police had arrested five others and they are currently in police custody.

Of the two arrested Thursday, a 33-year-old man was taken into custody on suspicion of being linked to commission, preparation or instigation of acts that may be related to terrorism. The other man, 40, was arrested on suspicion of possessing and supplying fake documents, BBC reported. Searches were also being conducted at five different residential addresses, from where five other men were arrested earlier in the week.

On Sunday, armed anti-terror officers from Scotland Yard and Kent police arrested two men, aged 33 and 43, from Dover. A day later, officials arrested a 28-year-old man, and two more men, aged 24 and 40, as part of the same operation, The Guardian reported. All five men are currently being held on suspicion of being linked to acts of terrorism.

In October, British authorities had said they are watching “thousands” of suspects in London who may be linked to terrorist activities. The country had also increased the threat level to “severe” in August after British Prime Minister David Cameron called fighters from the Islamic State group as the biggest threat to the country. In the same month, officials had also arrested four people, of whom one had links to the Islamic State group in Syria. The men had reportedly been under MI5 surveillance before their arrest.

London Mayor Boris Johnson has also said that home-grown terrorists pose the greatest threat to the city as nearly 600 people are estimated to have returned back after traveling to the Middle East to fight alongside jihadists from ISIS or al Qaeda.