BRUSSELS (Reuters) - NATO's head called Afghan President Hamid Karzai on Wednesday to express "deep concerns" about a surge in rogue attacks on foreign soldiers.

Afghan servicemen have killed at least 45 NATO-led troops this year, up from 35 in the whole of 2011, increasing mistrust between foreign soldiers and Afghan forces they are training.

In a telephone call with Karzai, NATO Secretary-General Anders Fogh Rasmussen "reaffirmed our continued commitment to the ISAF mission and emphasized that the strategy remains on track," spokeswoman Carmen Romero said.

"The secretary-general, however, also shared with President Karzai his deep concerns about insider attacks," she said.

Rasmussen outlined measures to try to stop the insider attacks that include strengthening vetting procedures, better counter-intelligence and cultural awareness training, and he urged Karzai to join in those efforts, Romero said.

"President Karzai assured the secretary-general that he is doing all he can to prevent the occurrence of such attacks," she added.

Rasmussen told Reuters in an interview on Monday that the alliance's plans gradually to hand over security to Afghan forces and pull out most troops by end-2014 would not be disrupted by the attacks.

(Reporting by Adrian Croft; Editing by Rex Merrifield and Robin Pomeroy)

(This story was refiled to change "ISAF" to "45 NATO-led troops" in the second paragraph)