KABUL, Afghanistan » Defense Secretary Robert M. Gates met here on Monday with President Hamid Karzai and Gen. Stanley A. McChrystal to review plans for a major U.S.-led offensive in the city of Kandahar, the spiritual heart and birthplace of the Taliban, an operation McChrystal indicated could get under way this summer.

McChrystal, the top NATO and U.S. commander in Afghanistan, declined to be more specific, but told reporters at a briefing in Kabul that it would be several more months before U.S., coalition and Afghan forces were at full strength around Kandahar, a city of 900,000 and the capital of Kandahar province.

The general said that while “;Kandahar has not been under Taliban control, it's been under a menacing Taliban presence, particularly in the districts around it.”; He said he had already sent more troops to those districts, and more would be on the way.

By early summer, he said, “;I think we'll have enough Afghan forces,”; adding that “;our forces will be significantly increased around there.”; At this point, only 6,000 of the 30,000 extra U.S. troops ordered by President Barack Obama have arrived.

McChrystal said that the Kandahar offensive would be different from a recent American-led campaign to largely rout the Taliban from Marjah, a much smaller town in Helmand province. While the Marjah offensive began with a burst of forces into the area in the middle of the night, McChrystal said that the Kandahar offensive would unfold more slowly.

“;There won't be a D-Day that is climactic,”; he said. “;It will be a rising tide of security as it comes.”;

Gates, at a news conference with Karzai later in the day, displayed some friction with Richard C. Holbrooke, the U.S. special representative to Afghanistan and Pakistan, who said Thursday at a forum at Harvard that almost every family of the southern Pashtun tribes in Afghanistan had someone involved with the Taliban movement.

The Pashtun make up Afghanistan's largest ethnic group, and its members dominate the Taliban, though some Pashtun tribes have turned against it.

Asked by a member of the Afghan news media about Holbrooke's comment, Gates replied, “;I have a great deal of respect for the senior representative for Afghanistan and Pakistan, Ambassador Holbrooke, but that doesn't mean that I agree with everything he says, including that.”;

The U.S. Embassy in Kabul almost immediately issued a clarification. In it, Holbrooke said that “;when I noted that almost every Pashtun family has someone involved with the movement”; he had been reflecting a recent comment by Karzai that the Taliban who were not part of terrorist networks or al-Qaida were “;sons of the Afghan soil.”;

Holbrooke added in the statement: “;I was not suggesting that all Pashtuns are part of the Taliban or all Taliban are Pashtuns.”;

Later on Monday, Holbrooke contacted The New York Times to say that Gates' comments had been based on an incomplete account of what Holbrooke said during his appearance at Harvard. According to a transcript provided by the State Department, Holbrooke told the Harvard audience that “;almost every Pashtun family in the south has family or friends who are involved with the Taliban—it's in the fabric of society.”;

Holbrooke said that his inclusion of “;friends”; in his description gave his statement a different meaning from that in accounts of his Harvard remarks, which included only his reference to “;family.”; He said that his remarks were similar to those of other administration officials, including Gates, who at a news conference in Islamabad, Pakistan, in January spoke of the Taliban's being “;part of the political fabric of Afghanistan.”;

Before arriving in Kabul, Gates told reporters on his plane that despite the success of the operation in Marjah, it was too early to expect reconciliation with some top Taliban members, as both the United States and Karzai would like.

“;I think we ought not to get too impatient,”; Gates said. “;I do believe that the senior Taliban are only going to be interested in reconciling in terms that are acceptable to the Afghan government, and those of us supporting it, when they see that the likelihood of their being successful has been cast into serious doubt. My guess is they're not at that point yet.”;

President Mahmoud Ahmadinejad of Iran is expected to meet with Karzai in Kabul this week.

Gates said Iran was “;playing a double game in Afghanistan—they want to maintain a good relationship with the Afghan government, they also want to do everything they possibly can to hurt us, or for us not to be successful.”; He said that Iran was providing money and “;some low level of support”; to the Taliban in Afghanistan.