SEOUL, South Korea (AP) — South Korea on Thursday walked back on a proposal to lift some of its unilateral sanctions against North Korea following U.S. President Donald Trump’s blunt retort that Seoul could “do nothing” without Washington’s approval.

Foreign Minister Kang Kyung-wha had said on Wednesday that Seoul was considering lifting measures applied after a deadly attack in 2010 that killed 46 South Korean sailors. She cited the intent to create more diplomatic momentum for talks over North Korea’s nuclear program.

South Korean conservatives reacted with anger as well, and Kang’s ministry downplayed her comments later, saying in a statement that the government has yet to start a “full-fledged” review of sanctions, meaning no decision was imminent.

Unification Minister Cho Myoung-gyon told a parliamentary audit on Thursday there has been no serious consideration given to lifting the sanctions and that doing so would be hard unless North Korea acknowledges responsibility for the 2010 attack. North Korea has fiercely denied it sank the Cheonan warship.

Liberal South Korean President Moon Jae-in hopes that progress in nuclear diplomacy will allow him to advance his ambitious plans for engagement with North Korea, including joint economic projects and reconnecting inter-Korean roads and railways. These projects have been held back by the sanctions against North Korea.

While arguing that improved inter-Korean relations could possibly facilitate progress in larger nuclear negotiations between the U.S. and North Korea, Cho said Seoul isn’t ready yet to campaign for reduced pressure against its rival.

“At the current stage, I think it’s a little early for us to call for the lifting or easing of the U.N. sanctions,” Cho said.

Trump’s response when he was asked about Kang’s comments implied friction between the allies over the pace of inter-Korean engagement amid concerns in Washington that North Korea is lagging behind in its supposed promise to denuclearize.

“They won’t do that without our approval,” Trump said of the comments. “They do nothing without our approval.”

Trump has encouraged U.S. allies to maintain sanctions on North Korea until it denuclearizes as part of what his administration has termed a campaign of “maximum pressure” against leader Kim Jong Un’s government.

Moon has mostly stayed firm on sanctions despite actively engaging with North Korea and floating the possibility of huge investments and joint economic projects in return for the North’s relinquishment of its nuclear weapons.

A move by South Korea to lift some of its sanctions would have little immediate effect since U.S.-led international sanctions remain in place. But it’s clear Seoul is preparing to restart joint economic projects if the nuclear negotiations between the United States and North Korea begin yielding results.