GENEVA - Attacks on medics in war zones are becoming more frequent and drawing less outrage, despite being explicitly forbidden under international law, the Red Cross said Wednesday.

The neutral aid group said recent incidents in Syria, Bahrain and Yemen indicated a wider trend toward targeting health care workers, hospitals and ambulances.

A report compiled by the Geneva-based International Committee of the Red Cross examined 655 incidents across 16 countries, including Afghanistan, Iraq, Israel, Sri Lanka and Colombia.

"This really is the tip of the iceberg," said Robin Coupland, a ICRC medical adviser and former war surgeon. "There are thousands upon thousands of such incidents."

Even when the attacks themselves cause few or no casualties, they can have an immense knock-on effect on local communities, depriving thousands of medical aid, Coupland said.

He cited Iraq, where half the doctors fled the country between 2003 and 2008 because of sectarian attacks, leaving entire communities without medical care.

Holdups at checkpoints, takeovers of hospitals and the increasingly urban nature of warfare where families accompany victims to hospital and suffer injuries on the way contribute to the problem, said Coupland.

ICRC director-general Yves Daccord warned that the attacks were prompting less outrage than they previously would have.

"What we are surprised about is how much these incidents almost go unnoticed," said Daccord. "People seem to get used to it."

He urged governments and armed groups to address the issue and take measures to prevent such attacks.

"We need to absolutely push for respect for the law" of armed conflict, outlined in the Geneva Conventions, Daccord said.