Washington remained on full alert today as the hunt continued for a serial sniper who has so far killed six people and wounded two.
Anxious parents accompanied their children to school or kept them at home after the attacker critically injured a 13-year-old boy yesterday.
Cafes and restaurants also closed outdoor sections as police said they were no closer to finding the killer who has brought panic to the US capital and surrounding suburbs.
"I would like to think I have got the words to keep people calm, but I'm not sure I do," said Montgomery Police Chief Mr Charles Moose.
"I have never been able to know exactly when we will be able to bring this to closure."
The sniper has struck eight times in the normally quiet Washington suburbs within the last week, each time with a single bullet. None of the victims are believed to have known each other.
The latest victim, who has not been named, was hit in the torso as his aunt dropped him at Benjamin Tasker Middle School in Bowie, Maryland.
He remains in a critical but stable condition at Children's Hospital in Washington. Doctors said they were optimistic he would survive.
Police said they were investigating more than 1,000 leads and have not ruled out the possibility that more than one person is involved.
Most of the victims were shot in broad daylight while doing everyday activities. There are no known witnesses who have seen the attacker.
PA