The U.S. military "is on track and will stay on track" to meet its Aug. 31 deadline to get down to 50,000 troops in Iraq, Chairman of the Joint Chiefs of Staff Adm. Mike Mullen said on on CNN's "State of the Union" Sunday.
"Right now the trends are moving in the right direction," he said.
Sen. Jim Webb (D-Va.) questioned whether the deadline could be met.
Despite an uptick in violence in the country during the past year, it hasn't resulted in a sectarian response, he said.
"Over the next couple of years we'll have the ability to get to a point where we are home twice as long as we are deployed," Mullen said. "So right now, as far as troop numbers are concerned, I'm comfortable."
While there is clearly a linkage between military operations in Iraq and Afghanistan, "We're not coming out of Iraq so we can support Afghanistan. Right now, with the plans we have, we can do both."
Troops in Afghanistan will be increased to about 100,000 by the fall, he said.
Recent meetings with Afghanistan President Hamid Karzai were "positive" and he is committed to a strategic partnership and "knows very clearly what he needs to do" to reduce government corruption and he has taken some steps, Mullen said.
"Clearly a lot more needs to be done but from my perspective President Karzai knows what he needs to do and we're moving in that direction," he said.
Operations in Kandahar "will really be critical and I think by end of the year, from a trend standpoint, we'll know whether this thing is headed in the right direction or not ," Mullen said.
He likened the province to Baghdad during the surge, saying control in the region will play a key role in what happens in the country.
There are a "complex set of relationships between the tribes that make that place tick or don't let it tick and it's reflective of the entire country," he said, as the U.S. continues working with its Afghanistan and coalition partners to bring jobs, medical supplies and other services lacking in the region.
The effort to help Afghanistan build a national army and police force is exceedingly difficult, especially in the absence of a stable national government, Webb said on CNN this morning.
Despite operations going well "tactically on the ground" it could be hard to put all of the diverse pieces together to achieve that goal, Webb said.