China is ramping up purchases of Greek bonds and will remain a long-term investor when Greece issues new debt, Premier Li Keqiang said on Thursday, in a show of support for the debt-laden country.

"We have never abandoned the Greek bond market, but we are increasing our purchases," Li said, speaking through an interpreter, at the start of a three-day visit to Greece.

"I have expressed my will to [Greek Prime Minister Antonis] Samaras that when Greece will issue new Greek bonds, China will continue being a long-term and responsible investor."

Athens returned to the bond markets in April after a four-year exile and is expected to issue debt again this summer.

Li also said the global economic recovery "still has many uncertainties and faces many challenges." He said China's economic growth target of 7.5 percent this year was "logical" and reiterated a CPI growth target of 3.5 percent.

"The Chinese economy is under pressure, but it is still growing at a steady pace," he said.