What is the meaning of "running up" in this context? In the passage below, "Anything that stems the flow of migrants in Libya also runs the danger of running up against the interests of the powerful armed groups that control the trade. In a country racked by conflict, migrant smuggling has become a lucrative business for a bewildering to cause physical or mental pain, or trouble, to someone or something producing a lot of money confusing and difficult to understand array of criminal gangs and associated militias." What is the meaning of "running up"? I checked an on-line dictionary and found the following definitions: 1. Make or become greater or larger 2. Accumulate 3. Sew rapidly 4. Raise a flag but any of them does not seem fit? I assume it means to make actions against the military groups but it is not clear. Is there any idiom like "run the danger of running up against sth"? Thanks in advance?