Ministers will "check" that Britain has sufficient measures in place against non-Islamist terror threats in the wake of the Norway attacks, William Hague has said.
Prime minister David Cameron will chair a meeting of the national security council on Monday after 92 people were killed in Norway on Friday.
Suspect Anders Behring Breivik, a 32-year-old Norwegian national, has claimed his shooting on a youth camp on Utoeya island, which left at least 85 dead, was "gruesome" but "necessary", according to his lawyer.
He is thought to have links with right-wing extremist groups, prompting the British government to reassess its own readiness to prevent and cope with a similar incident in the UK.
"We will look at the lessons to be learned from this," Mr Hague told BBC1's The Andrew Marr Show.
"We will check enough attention is being given to all forms of terrorism."
The foreign secretary insisted that Britain had "strong defences" in place, including tight firearm controls, restrictions on the sale of material needed to manufacture a bomb and highly trained firearms officers.
Mr Breivik is thought to have been motivated by Muslim immigration and anger against multiculturalism. He appeared in a YouTube video called Knights Templar 2083.
"We must not think because of this event that al-Qaida-inspired terrorism is not a threat," Mr Hague added.
"It remains in all assessments the single biggest terrorist threat to the United Kingdom. In our counter-terrorism strategy it's very clear it's not the only form or threat we may face."
Britain is offering its experience of dealing with similar incidents.
Local authorities, police forces and individuals have experience of dealing with incidents like the Dunblane or Cumbria shootings, Mr Hague explained.
The home secretary has also offered assistance to her Norwegian counterpart if needed.
"Norway doesn't have that experience - that is one of the reason why this is such a profound shock there," Mr Hague added.
"This is the worst event in Norway since the end of the Second World War. If necessary we will have people visit Norway and give people the benefit of our advice and experience."
Mr Breivik is set to appear in court on Monday.
In Oslo, searches are continuing amid the rubble amid fears that the death toll, currently at seven, will rise further.
"We will work with Norway to hunt the murderers who did this and prevent any more innocent deaths," Mr Cameron said in a statement on Friday.
"We can overcome this evil, and we will."
Labour leader Ed Miliband, also speaking on Friday, said: "I'm horrified by events in Norway.
"These senseless acts are an affront to decent people everywhere. All my thoughts are with the Norwegian people."