Last year, many of the world's deadliest crises intensified. In its annual outlook for 2019, Crisis Group seized turmoil in the international order, erosion of global norms, and leaders extending their influence by meddling in foreign wars. Here are the 10 complex crisis groups we'll be watching most closely this year. First Yemen, which already suffers the world's gravest humanitarian crisis could get worse in 2019. UN officials say that if the key port of Hadehda comes under attack, parts of the country could suffer famine. Fighting in Afghanistan took more lives last year than any other war on the planet. Without progress in peace talks among the Taliban, the United States and the Afghan government, this year's death toll could be even higher. China-US tensions are not a deadly conflict despite their trade war. Still, rhetoric from both sides is increasingly bellicose. If relations worsen, the rivalry could have grave or geopolitical consequences than all the other crises. In the Middle East, rivalry risks escalating between, on one side, the US, Saudi Arabia and Israel, and on the other, Iran, a clash at any of the region's many flashpoints could provoke a wider confrontation. In Syria, mixed messages from President Trump about the potential withdrawal of US forces increased the odds of a bloody conflict involving Turkey, its Syrian allies, Kurdish forces and the Assad regime. This could give ISIS a new lease of life. Nigerians go to the polls early in 2019 amid especially combustible electoral conditions. Boko Haram militants are resurgent and the country is experiencing unprecedented levels of violence between farmers and herders. In South Sudan, five years of civil war have already killed 400,000 people. If a recent power sharing deal between the President and rebels collapses, it could provoke a new bout of violence. Fighting in Cameroon's Anglophone areas is close to civil war. As nearly 10 separatist militias battle government forces, the crisis has displaced half a million people. Without talks between the government and Anglophone leaders, it is likely to get worse. In Ukraine, sporadic fighting in the eastern Donbass region continues with civilians paying the price. Another flashpoint is the Sea of Azov, where Russian and Ukrainian ships clashed in November. Last is Venezuela. The economy is in freefall. One of 10 Venezuelans has fled the country with more leaving daily. Latin American leaders are struggling to convince President Maduro to accept a transition of power. These are crisis groups, top 10 conflicts to watch in 2019. We will be making every effort to help bring peace to these and many other crises worldwide.