The US and Iranian militaries are engaged in a dangerous build-up of forces in the Gulf.
Although each side appears to be signalling to the other not to escalate the tension between them, the build-up carries the risk of sparking an incident.
Iran's Revolutionary Guards have launched several missiles as part of a military exercise timed to coincide with the introduction of an EU oil embargo, which is aimed at forcing Iran to fully co-operate with the UN over its nuclear programme.
The unit fired short range missiles capable of hitting US warships in the Gulf, and longer range versions which could hit US troop concentrations in the region.
State TV was invited to film the exercises and give the footage to international TV agencies.
Iran also chose this week to announce that it had produced an anti-radar missile called 'Arm' that can strike any radar source.
Tehran claims the missile can travel at several times the speed of sound and has a range of 300kms.
This public display is in contrast to the American activity, which has been conducted quietly albeit not in secret.
According to the New York Times (NYT), the US Navy has moved extra ships and aircraft into the Gulf.
The number of minesweepers has doubled to eight, signalling to Iran that any attempt to mine the narrow Strait of Hormuz in the Gulf will be countered.
The US has introduced F-22 and F-15C warplanes to two bases in the region to reinforce the fighter jets it already has in place.
These are capable of devastating Iran's coastal defences and can reach deep inside the country.
The NYT says a converted transport ship has also been moved to the Gulf and could act as an amphibious staging base for military operations.
The Americans say their moves are defensive and aimed at preventing action by Iran. The Iranians say the reverse is the case, that the country needs to test its missiles to counter an aggressive America.
In the current atmosphere, there is the danger that a relatively minor incident could trigger a bigger confrontation.
The Gulf is a small area in which to place so much firepower.The US and Iranian militaries are engaged in a dangerous build-up of forces in the Gulf.