DUBAI (Reuters) -Supreme Leader Ayatollah Ali Khamenei said on Saturday Iran will not be bullied into negotiations, a day after U.S. President Donald Trump said he had sent a letter to the country's top authority to negotiate a nuclear deal.

In an interview with Fox Business, Trump said "there are two ways Iran can be handled: militarily, or you make a deal" to prevent Tehran from acquiring nuclear weapons.

At a meeting with senior Iranian officials, Khamenei said the aim of Washington's offer for negotiations was to "impose their own expectations", Iranian state media reported.

"The insistence of some bullying governments on negotiations is not to resolve issues ... Talks for them is a pathway to have new demands, it is not only about Iran's nuclear issue ... Iran will definitely not accept their expectations," Khamenei was quoted as saying, without directly mentioning Trump.

While expressing an openness to a deal with Tehran, Trump has reinstated a "maximum pressure" campaign that was applied during his first term as president to isolate Iran from the global economy and drive its oil exports to zero.

During his 2017-2021 term, Trump withdrew the United States from a landmark deal between Iran and major powers that placed strict limits on Tehran's nuclear activities in exchange for sanctions relief.

After Trump pulled out in 2018 and re-imposed sanctions, Iran breached and far surpassed those limits.

U.N. nuclear watchdog chief Rafael Grossi has said time is running out for diplomacy to impose new restrictions on Iran's activities, as Tehran continues to accelerate its enrichment of uranium to near weapons-grade.

Tehran says its nuclear work is solely for peaceful purposes.

Khamenei, who has the last say on Iran's key policies, said there was "no other way to stand against coercion and bullying".

"They are bringing up new demands that certainly will not be accepted by Iran, like our defence capabilities, missile range and international influence," he was quoted as saying.

Although Tehran says its ballistic missile programme is purely defensive, it is seen in the West as a destabilising factor in a volatile, conflict-ridden Middle East.

Tehran has in recent months announced new additions to its conventional weaponry, such as its first drone carrier and an underground naval base amid rising tensions with the U.S. and Israel.

(Writing by Parisa Hafezi; Editing by Sharon Singleton and Timothy Heritage)