The U.S. Transportation Security Administration's Peter Neffenger said Friday he would like to see explosive-sniffing dogs at all of the nation's largest airports. 

The dogs would allow cleared passengers to pass directly into "pre-check" lanes that include a metal detector but do not require passengers to remove their shoes or bagged liquids, Neffenger said. 

"I would likely to dramatically increase the number of dogs we have," Neffenger told reporters at TSA headquarters.

The transportation oversight agency currently uses 222 dog teams to sniff for explosive materials around cargo, 140 of which are trained to sniff passengers as well. 

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Neffenger said he would like all of the dog teams to be trained to sniff passengers by the end of the year or the beginning of 2017. 

Though his term as TSA head is due to end when President Barack Obama leaves office in January 2017, Neffenger's goal is for TSA to deploy 500 dog teams at all of the high-volume U.S. airports some time after his departure.

The dogs are acquired by the U.S. Department of Defense from breeders in Europe and take about 10 months to train, Neffenger said. That training time limits how many dogs he can deploy immediately. 

Neffenger said replacing the current security screening procedure used by most passengers with bomb-sniffing dogs would speed up lines at airports. 

Those lines at security checkpoints are both inconvenient for travelers and also create a security risk.

Neffenger, who happened to be landing at the Brussels airport shortly after it was attacked on March 22, said moving lines would make it harder for attackers to pinpoint an area to cause maximum devastation.