Trump issued the threat after North Korea yesterday exploded a thermonuclear device in its sixth and most powerful nuclear test. The threat was seen as a warning to China, North Korea's main trading partner and only major ally.
A foreign ministry spokesman, Geng Shuang, criticized Trump's stance as unfair to Beijing.
"What is definitely unacceptable to us is that on the one hand we work so hard to peacefully resolve this issue and on the other hand our interests are subject to sanctions and jeopardized," Geng said at a regular news briefing. "This is unfair."
Trump said it was under consideration "in addition to other options."
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Asked whether Beijing would support tougher UN sanctions such as cutting off oil supplies to North Korea, Geng didn't mention oil but said whatever happened would depend on discussions among council members. Geng said China, one of five permanent Security Council members with power to veto UN actions, would take part in a "responsible and constructive way."
Geng expressed frustration at Australian Prime Minister Malcolm Turnbull's comment that Beijing had a responsibility to influence North Korea due to its status as the North's main trading partner.