Washington (CNN) The FBI received more than 38,000 tips from the public during the first full week of August following the shooting deaths of 31 people in El Paso, Texas, and Dayton, Ohio, a bureau official said.

The tips, submitted to the agency's National Threat Operations Center, is a significant increase as the FBI has received an average of 22,000 tips per week this year. The official said the number of threats it receives varies each week, but the fluctuation shows more people called the center following the mass shootings in Dayton and El Paso on August 3 and 4.

The official also said not all tips called into the NTOC become active FBI investigations and some are passed on to local law enforcement. Not all tips it receives are actionable and some tips are not really tips at all, and some tips are people giving their opinions or thanking the agency for its work.

In a statement, the FBI cautioned people to "remain vigilant and report any and all suspicious activity to law enforcement immediately."

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