Even though the Iraqi forces, backed by a US-led global coalition, have achieved their biggest success against ISIS by liberating the key city of Mosul, the war against the terrorist group is not over yet, says a top envoy. "This thing is not over at all. We have some ways to go. And that's why we had the meeting today, really to coordinate our efforts for the next phase," Brett Mcgurk, the top US envoy for the international coalition against the Islamic State group, told reporters during a news conference here. Liberation of Mosul, he said, is one of the biggest events in the war against ISIS. This has been an year-long campaign in Mosul, that kind of culminated just over the last few days, he said and described the Mosul campaign as one of the most difficult military operations since World War II. This was a campaign in a city of 1.5 million people, with an enemy that had barricaded amongst the population, he noted. During the meetings in Washington DC on ISIS, he said the government of Iraq made very important presentations not only to the coalition, but to the World Bank earlier this week, about its longer-term reform effort and reconstruction needs. McGurk said Raqqa and Syria is much more complicated than Iraq, but a fairly similar model, working by, with and through partners, and preparing the ground for basic humanitarian and stabilisation relief efforts today. While a lot depends on political reconciliation, the US envoy said the rise of ISIS was mainly due to the 40,000 foreign fighters who poured into Syria over the course of about four years. "These are the foreign fighters, the hard-core terrorists, the suicide bombers. And so you had in Iraq a situation in which, you know, 2010, '11, '12, about five to ten suicide bombers a month,..that's kind of extraordinary to think about," he said. "That went up last year almost to 100 suicide bombers a month. And even in 2014, it went up to 60-70 a month. "Any country, if you have all these people coming from all around the world to blow themselves up in mosques, ice cream parlors, killing children, killing children in soccer games, this is what was happening in Iraq," he said. "So as long as you have that going on, from all these people from all around the world, it's very difficult to talk about political progress, quite frankly. "So as we defeated ISIS on the ground and we pushed them out of their territory, we have also worked to shut down the flow of those foreign fighters," the US envoy said. According to him, the foreign fighters are not coming into Syria anymore. "Those who are already in Iraq and Syria, we've been working very hard to make sure that they can never get out," he said. Ethiopia is the latest country to join the international coalition, he added.