Talks between the U.S. and China to resolve their yearlong trade standoff appeared to be on life support Monday, with Beijing struggling to respond to a pair of tweets by President Donald Trump that threaten an escalation of tariffs by the end of the week.

China¡¯s foreign ministry said that officials were still planning to travel to the U.S. for the next round of talks ¡ª but was unable to confirm when amid signs that a delay is now being considered. Meanwhile, a media blackout on Trump¡¯s threat left investors baffled as stocks and the yuan tumbled on rumors that the trade war is now back on.

¡°We are now trying to get more information on the relevant situation,¡± ministry spokesman Geng Shuang told a briefing in Beijing. ¡°What I can tell you is that the Chinese team is preparing to travel to the U.S. for trade talks.¡±