From CNN Security Clearance:  President Obama is "deeply concerned" about the growing number of deadly attacks on U.S. forces by Afghan security forces, and plans to contact the Afghan president to discuss taking tougher actions, he said Monday.

"I’ll be reaching out to President (Hamid) Karzai," Obama told reporters at the White House, adding, "We’ve got to make sure that we’re on top of this."

Obama spoke Monday with Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff. The top U.S. military official is in Afghanistan for meetings with coalition and Afghan leaders, including Gen. John Allen, commander of NATO forces, and Afghan Army Gen. Sher Mohammad Karimi, Dempsey’s counterpart in the country.

There has been some success, including better counterintelligence, Obama said. "But obviously we’re going to have to do more."

"And hopefully over the next several weeks we’ll start seeing better progress on this front," he added.

An incident Sunday brought the death toll in attacks by Afghan military and police personnel this year to 40, according to U.S. military officials.

Twenty-three of those killed were Americans, according to the U.S. Defense Department.

The NATO death toll in what the military is now calling "insider attacks" is already higher than it was last year, according to statistics compiled by the New America Foundation, a public policy think tank.

NATO’s International Security Assistance Force said Friday that 39 people had been killed in these attacks in 2012. That was before Sunday’s attack killed one ISAF service member. . . .

Officials are examining the vetting process for Afghan soldiers and police "and investigating where it failed," a Defense Department statement said.

All troops at NATO headquarters and all bases across the country have been ordered to carry loaded weapons around the clock, CNN learned Friday.  (photo: CNN)

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