Three more foreign soldiers, reported to be US marines, were killed at a NATO base Friday night following a similar attack Friday morning, which also left three US soldiers dead in the same region. The day was the bloodiest single day for foreign troops in the southern Helmand province since six British soldiers were killed by a roadside bomb in early March.

The shooters in the first case were Afghan police, assumed to be allies of the US. On Friday morning an Afghan commander and some of his men invited the US officers to join them for a meal and to discuss security before shooting them.

In the evening incident, the shooter who killed three other foreign soldiers, has not yet been identified as security personnel, but worked with the US soldiers on a joint base.

The attacks were the third and fourth green-on-blue attacks in less than one week. Such attacks have continued to rise steadily over the last several years. So far this year 37 soldiers and military contractors have been killed in 27 such attacks, far more than in 2011.

This trend, according to foreign policy experts, Common Dreams reported Friday, has long been on the rise in Afghanistan, and the most recent incidents speak to a US war strategy in tatters.