Foreign Ministry spokesman Bahram Qassemi said Monday Iran welcomes any effort for peace in the Korean peninsula as North Korea's Kim Jong-un and US President Donald Trump arrived in Singapore for the historic meeting.
"We are interested that peace, stability and security is established in the Korean peninsula like other places in the world and any step which helps this process and the economic development and prosperity of the region, we welcome it," he said.
"However, given what we know from the US track record and its history of behavior and relationship, especially from Mr. Tramp, who in his presidency has taken steps based on sabotage, exiting agreements and breaching obligations, especially with regard to the JCPOA, we do not have an optimistic outlook toward this issue," he said.
US and North Korean officials held talks on Monday in a late bid to narrow differences before Kim and Trump meet in order to end a nuclear standoff on the Korean peninsula.
Key gaps remain over what denuclearization would entail for two countries and the officials were trying to push the agenda forward before their leaders meet on Tuesday.
The summit comes just over a month after the US president pulled out of the landmark nuclear deal with Iran and other world powers, known as the Joint Comprehensive Plan of Action (JCPOA).
Qassemi said, "We believe that the Korean government should deal with this issue very carefully, because the nature of the American regime is not something to be optimistic about."
"We support peace and security that is in the interests of the peninsula, but we look at American behavior with pessimism," he added.