ISLAMABAD (Reuters) - A roadside bomb exploded near the seafront in Karachi on Tuesday likely targeting a van full of Chinese port workers, police said, a day before Chinese Premier Li Keqiang arrives in the capital, Islamabad. No one was hurt. Karachi, the nuclear-armed country's key port, is home to 18 million people. It typically sees about a dozen murders a day, a combination of political killings, attacks by the Pakistan Taliban and sectarian militant groups, and street crime. "Apparently, the Chinese who are working at the harbour were the target of the explosion," senior police officer Nasir Aftab told Reuters. Li arrives in Islamabad on Wednesday on the second leg of his first official trip since taking office in March after a visit to Pakistan's arch rival, India. Pakistan and China consider each other "all-weather friends". Their close ties have been underpinned by wariness of India and a desire to hedge against U.S. influence across the region. In 2004, two Chinese engineers working in Pakistan were kidnapped by the Pakistan Taliban. One was later rescued but the other killed.