Iran's foreign minister on Saturday dismissed the possibility of war erupting in the region, but a top military commander criticised the US political system, saying it has "osteoporosis", state news agency Irna reported.
The statements come days after drone attacks on Saudi oil pumping stations that Saudi Arabia blamed on Iran-backed rebels in neighbouring Yemen, and in the same week that four oil tankers were sabotaged off the UAE's Fujairah coast.
The incidents added to already heightened tensions in the region after the tightening of US sanctions on Iran, particularly its vital oil exports, and the deployment of US warships and bombers to the region.
"There will be no war because neither do we want a war, nor has anyone the idea or illusion it can confront Iran in the region," Foreign Minister Mohammad Javad Zarif told Irna before ending a visit to Beijing.
Tensions between Washington and Tehran have increased in recent days, raising concerns about a potential US-Iran conflict. Earlier this week, the United States pulled some diplomatic staff from its Baghdad embassy.
"The fact is that Trump has officially said and reiterated again that he does not want a war, but people around him are pushing for war on the pretext that they want to make America stronger against Iran," Mr Zarif said.
In Tehran, Major General Hossein Salami, the commander of the Revolutionary Guards, said on Saturday that Iran had nothing to fear from the United States, which he said was in decline, the semi-official news agency Isna reported.
"The US political system is full of cracks. Though impressive-looking, it has osteoporosis. In fact, America's story is like the World Trade Centre towers that collapse with a sudden blow," Mr Salami, known for his fiery rhetoric, was quoted as saying in referrence to the Sept 11, 2001 attacks.
Mr Trump has said he wants to pursue a diplomatic route with Iran after ratcheting up pressure on Tehran.
President Hassan Rouhani said on Saturday that Iran would not be bullied into negotiating, Irna reported.