Spain has boosted security measures at sensitive points and redoubled counterterrorism efforts, the interior ministry has said, as other European countries said they faced an increase in extremist threats amid rising tensions in the Middle East.
The move comes as Israel launched a military offensive to root out Hamas fighters in the besieged Gaza Strip after militants killed 1,300 people in a rampage through Israeli towns earlier in October.
The killing of a teacher in France last week and two Swedish football fans in Belgium on Monday led French President Emmanuel Macron to say Europe was seeing a rise in "Islamist terrorism" that threatened all states in the region.
Spain has kept its state of terror alert at level four - the second-highest on a five-point scale - since Islamist militant attacks in Paris in June 2015. However, officials said they would ramp up national security within that level.
This would include "the strengthening of security measures at certain particularly sensitive points throughout the national territory and the increase in counter-terrorist efforts", the ministry said in a statement without specifying more concrete measures.
Around 700 police officers are set to be deployed today in the coastal city of Valencia after a European basketball league game between Valencia Basket and Israel's Maccabi Tel Aviv was declared "high risk" by the central government's regional office.