Mr Li told a summit with central and eastern European leaders yesterday that China would stick to the path of opening its markets and other reforms that had fuelled its economy, providing opportunities for European Union members and aspirants in the bloc's poorer half.
The U.S. imposed 25 percent duties Friday on $34 billion worth of imports from China.
China has promised billions of dollars for development projects in central and eastern Europe as part of its Belt and Road strategy to carve out new export markets.
Countries around the world were affected by the global financial crisis that started in 2008 and which led to banking crises and the so-called "Great Recession", especially in the US and Europe, where growth has improved over the past few years.
He hopes that this round of inter-governmental consultations will release a strong signal to the world, and allow efforts to improve global governance to be a new growth point for China's relations with Germany and the EU. EU officials are in part anxious that subsidized Chinese companies will have a market advantage without reciprocal deals for European firms.
China and the 16 countries at the summit "need to carefully study how our cooperation can fit in with the European Union laws and regulations", Li said.
Friday's long-expected tariff volley fuelled fear that a prolonged and escalating battle would deal a blow to global trade, investment and growth, while also damaging US farmers who stand to lose revenues and potentially driving up food prices in China.
The project aims to combine road, rail, river and sea transport by linking by rail the Greek cities of Thessaloniki, Kavala and Alexandroupolis to Burgas, Varna and Ruse in Bulgaria and is expected to attract large investors from the Middle East, China, Russia and other major markets, the Bulgarian government said back then.
Although the US trade war with China wasn't initially on the agenda, it was an unavoidable topic for the host country and its Chinese visitor.
Analysts have said Li, who will travel to Germany on Sunday ahead of a wider China-EU summit in Beijing, would avoid any issues that might irk western EU governments. "Unity between China and Europe and cooperation between us can ensure peace and stability in the whole world".
Li expressed the expectation to consolidate China-Bulgaria traditional friendship and promote practical cooperation in various fields through this visit, so as to elevate China-Bulgaria comprehensive friendly cooperative partnership to a new level.
Li's Europe tour is being made at the invitation of Borissov and German Chancellor Angela Merkel.
"First and foremost, our cooperation is of win-win and mutual benefit", Li insisted.