US President Barack Obama and his Afghan counterpart Hamid Karzai reaffirmed their commitment to Afghanistan on Sunday after the death of 38 troops in a helicopter crash, the White House said.

Thirty US soldiers, reportedly including some two dozen special forces, were killed when Taliban insurgents shot down a Chinook transport helicopter Friday in the deadliest attack on coalition forces of the decade-long war.

Seven Afghan commandos and an interpreter were also killed in the attack.

"President Obama received a call today from President Karzai of Afghanistan, who reiterated his condolences for the tragic loss of 30 American service-members," the White House said in a statement.

"President Obama noted the extraordinary service of the Americans who gave their lives, and expressed his condolences for the Afghans who died serving by their side," it said.

"The two presidents reaffirmed their commitment to the mission in Afghanistan, which is critical to the security of both our countries."

It said Obama had also placed calls to several military commanders to express his condolences and reaffirm US support for the troops.

US media reported that the dead included members of the Navy's SEAL Team Six, the secretive unit behind the daring raid that killed Osama bin Laden.

Administration sources interviewed by AFP declined to comment on whether the dead included any Navy SEALs or Team Six members, but said the casualties did not include anyone who took part in the bin Laden raid.