David Cameron has said he is confident that security preparations for the London Olympics are on schedule.
On a visit to HMS Ocean, which is berthed at Greenwich, east London, for the Games, the Prime Minister also paid tribute to the military personnel on duty.
When questioned about security preparations, Mr Cameron replied: "I'm confident they're on track.
"I chair the Cobra meetings that have crunched through the decisions and made the necessary decisions to bring more military forces to bear."
Mr Cameron spent around an hour on board the Royal Navy's largest warship.
Ocean is acting as a launch pad for 10 Lynx helicopters which can fly RAF and Royal Marine snipers over the skies of London.
The ship is also accommodating around 300 military personnel who will provide security at nearby Greenwich Park, which is the venue for equestrian events.
Mr Cameron added: "The security of the Olympics is absolutely vital.
"We have very worked out plans for all eventualities and I wanted to come and thank some of the people that are responsible for that and that's why I'm here today.
"But now it's exciting because we're only two days away from what's going to be an incredible show.
"A great moment for Britain, a great moment for our athletes but also a great moment for all of our country and I think we want to make the most of it as a country."