US and allied troops have pushed back Taliban insurgents in a major offensive in Afghanistan but there is still a long way to go, U.S. President Barack Obama said on Saturday. “We knew that this summer was going to be tough fighting. They (the Taliban) have, I think, been pushed back but we still have a long way to go. We've got to get through elections,” he said in an interview with Reuters during his visit to Ghana. He said the United States and its allies would have to evaluate the situation after Afghanistan's Aug. 20 presidential election to see what more they could do. “It may not be on the military side, it may be on the development side,” he said. Asked whether Washington still needed British forces in Afghanistan now that it was ramping up its forces there, Obama said: “The contribution of the British is critical.” Meanwhile, Gunmen ambushed five police officers and a forestry official responding to reports of a dead body in northwestern Pakistan, killing all six, police said Sunday. No group immediately claimed responsibility for the attack, but authorities did not rule out Taliban militants, though other insurgent groups operate in the region. The ambush took place late Saturday in a forested area in the Mansehra district, an area believed home to several training camps for militants involved in the conflict with India over the divided Kashmir region. A bullet-riddled body of an unknown man also was found at the scene, police officer Rashid Khan said. The gunmen also set fire to the responding police van and took the victims' weapons, Khan said. The attack came as Pakistan's military continued to battle militants in the Swat Valley and the South Waziristan tribal region.