The US secretary of defence, Jame Mattis, has suggested the US and South Korea could resume large scale military exercises, as negotiations with North Korea over its nuclear weapons program stall.

President Donald Trump announced the suspension of drills, which have long drawn the ire of Pyongyang, in the wake of his summit with North Korean leader Kim Jong-un in Singapore in June. But since that historic meeting, there has been little progress toward the US goal of North Korean denuclearisation.

“As you know, we took the step to suspend several of the largest exercises as a good-faith measure coming out of the Singapore summit,” Mattis said at a news conference on Tuesday. “We have no plans at this time to suspend any more exercises.”

Restarting military drills would likely infuriate North Korea, which has in the past responded to the annual drills with threats of force. But the comments highlight frustrations within the US administration over stalled nuclear negotiations.

The Ulchi Freedom Guardian exercises were originally scheduled to take place this month, but were halted in an effort to encourage talks with North Korea. There has been no decision on large scale drills scheduled for early next year, Mattis said. Trump’s announcement in June that drills would be suspended took South Korean and American officials by surprise, and was widely seen as a large concession.

“This is a concrete example of how badly the administration has mismanaged talks, military exercises, and alliance relations,” Adam Mount, director of the Defense Posture Project at the Federation of American Scientists, wrote in response to the announcement.

“If future exercises are suspended, [North Korea] will say it was expected, perhaps required for talks to continue. If the exercises resume, it will damage talks and relations with Seoul.”

Mattis’s comments come less than a week after Trump abruptly cancelled a trip by US secretary of state Mike Pompeo to Pyongyang, prompted by a strongly worded letter from North Korean officials.

North Korea warned the negotiations are “again at stake and may fall apart” and if talks break down Pyongyang could restart “nuclear and missile activities”, according to a report by CNN.

The letter was sent by Kim Yong-chol, a senior advisor to Kim Jong-un and former head of the country’s spy agency. The letter said North Korea felt talks had stalled because “the US is still not ready to meet [North Korean] expectations in terms of taking a step forward to sign a peace treaty”.

The 1950-53 Korean war ended in an armistice instead of a formal peace declaration, meaning the United Nations forces led by the US technically remain at war with the North. North Korea’s state run media has repeatedly called in recent weeks for peace talks to come before nuclear negotiations.

In the wake of the cancelled trip, state media accused the US of “double dealing” and “hatching a criminal plot”.

Vipin Narang, a politics professor at the Massachusetts Institute of Technology, described US strategy as being “in a state of total disarray”.

“Any work toward denuclearisation had to be preceded by trust/peace building,” he wrote in a Twitter post. “Trump wasn’t listening. And here we are.”