President Barack Obama pledged full US cooperation to Afghan counterpart Hamid Karzai, Kabul said Wednesday after the US leader agreed to send 17,000 extra troops to the war-torn country. Obama and Karzai spoke by telephone -- apparently for the first since Obama took office nearly a month ago, Karzai's office said after the US leader approved extra troops "to stabilise a deteriorating situation". The statement did not say whether Obama referred to his approval of the new troops, announced early Wednesday Kabul time. Obama "assured his Afghan counterpart Hamid Karzai that his country will continue its help and cooperation in all aspects particularly in the war against terrorism," the statement said.