The volatile security situation in Afghanistan underscores the need for a robust military presence there, says the top US commander in the troubled country.

In an interview with USA Today on Tuesday, Army General John F. Campbell, commander of US and NATO forces in Afghanistan, said it is vital to keep the number of US troops in Afghanistan at the current level and delay their planned reduction as long as possible.

"My intent would be to keep as much as I could for as long as I could," Campbell said over the phone from Kabul. "At some point it becomes physics. I'm going to have to get them out.”

Currently there are 9,800 US forces in the country, reportedly training and consulting Afghan security forces. The number is slated to be halved by January 1, 2017, as part of President Barack Obama’s revised plans to leave the country.

The new plan means that Obama will not be able to deliver on his promise to bring home American forces from Afghanistan before he leaves office.

Campbell soon will return to Washington to brief civilian leaders on the security situation in Afghanistan and the required number of troops to fulfill the mission.

The general declined to offer specifics on his recommendations, saying they were classified, according to the report.

"Some of them will not go over well with people," he said. "Some of them will get approved."

Campbell also said he will not hesitate to ask for more troops for Afghanistan if necessary.

"My job as commander on the ground is to continually make assessments," he said. "Every time I have gone to the president and said, 'I need X,' I have been very, very fortunate that he has provided that. So he has been very flexible. It is actually been conditions-based as we have gone forward.”

The remarks came days after six US forces were killed in the war-torn country.

US officials have already announced that Washington intends to maintain a large counter-terrorism capability of drones and Special Operations forces to fight militants in Afghanistan.