BOGOTA (Reuters) - Colombia will increase protection for presidential candidates ahead of elections this month, the police said on Tuesday, after contenders from across the spectrum reported assassination plots against them.

Voters will go to the polls on May 27 to elect a successor to President Juan Manuel Santos, who leaves office in August.

Right-wing candidate Ivan Duque said last week assailants had planned to attack his campaign headquarters with explosives, while left-wing candidate Gustavo Petro said there were plans to assassinate him.

Ex-president Alvaro Uribe, Duque’s mentor, said on Monday the national intelligence agency had informed him of a possible attack on his life that involved Colombians and foreigners.

The police have said they are investigating the reports of potential attacks.

“We don’t underestimate any kind of information of this kind,” General Jorge Hernando Nieto, the head of the national police, told journalists.

The police will not skimp in any way on security for the candidates or others who are threatened, Nieto said, though he declined to give details about increased protection efforts.

Besides armed guards from the police and the national protection service, candidates’ security also includes armored vehicles and the use of bulletproof vests.

The safety of Colombian politicians has improved markedly since a low point in 1990, when presidential candidates Luis Carlos Galan, Bernardo Jaramillo Ossa and Carlos Pizarro were murdered in attacks attributed to drug trafficking gangs allied with right-wing paramilitaries.