Plans for a face-to-face meeting with Afghan President Hamid Karzai were scrapped at the last minute. Instead, the two leaders spoke by phone, Obama at the air base and Karzai in Kabul.

Under intense security, Obama landed in darkness after a clandestine departure from the White House on Thursday, where plans of his trip into the war zone were tightly guarded. Obama stepped off Air Force One just after 8:30 p.m. local time, clad in a leather jacket.

He was to personally thank US troops for their service during the holidays.

The White House said rough weather forced the president to abruptly drop plans to meet Karzai in Kabul. The White House determined the wind, dust and cloud cover made it unsafe for the president to fly by helicopter from the huge military complex here to the presidential palace.

In a rapidly changing sequence of events, the White House then said the two would speak by secure video conference — then said that, too, was dropped.

His visit to thank troops came ahead of an upcoming full review of his war plan later this month. On the flight, the White House said the review would include no major policy changes.

The president's visit came on a day when revelations of US diplomatic cables portrayed Afghanistan as rife with graft to the highest levels of government, with tens of millions of dollars flowing out of the country and a cash transfer network that facilitates bribes for corrupt Afghan officials, drug traffickers and insurgents.

Details from a vast tranche of cables released by the WikiLeaks website could further erode support for the nine-year war. After applying heavy public pressure on Karzai to fight corruption, US and NATO officials have switched to nudging him quietly so as not to undermine the very government the international community is trying to strengthen as an alternative to the Taleban.

The leaked cables also could bolster the concerns of US lawmakers who have threatened to hold back aid until they are convinced the money will not end up lining the pockets of the political elite.

A main concern in the cables appears to be Karzai himself, who emerges as a mercurial figure. In a July 7, 2009, cable, US Ambassador Karl Eikenberry describes "two contrasting portraits" of the Afghan president.

"The first is of a paranoid and weak individual unfamiliar with the basics of nation building and overly self-conscious that his time in the spotlight of glowing reviews from the international community has passed," the cable says. "The other is that of an ever-shrewd politician who sees himself as a nationalist hero. ... In order to recalibrate our relationship with Karzai, we must deal with and challenge both of these personalities."

In early February during a meeting with a US Embassy official, Abdul Salam Zaeef, the Taleban's former ambassador to Pakistan, said Karzai is deceiving all sides.

"When he sits with me, he tells me he wants the foreign troops to leave, then he tells you he wants them to stay forever, and he tells yet a third story to Islamic leaders of other countries," Zaeef said.