A top Iranian diplomat expressed disappointment on Sunday after meeting a minister from Britain's Foreign Office amid escalating regional tensions, saying the talks were "repetitive", the country's news agency IRNA reported. 

Minister of State for the Middle East Andrew Murrison had the "usual talking points", said Kamal Kharazi, the head of the Strategic Council of Foreign Relations at Iran's Foreign Ministry. 

These included saying a European payment mechanism to help Iran with U.S. sanctions "will soon become operational, that Britain has always supported the Joint Comprehensive Plan of Action (JCPOA) and has its own problems with America ... such talks that have always been repetitive," Kharazi added. 

The JCPOA is a multilateral 2015 nuclear deal that the U.S. unilaterally withdrew from in May last year. 

Arriving in Tehran Sunday,  Murrison met Kharazi and was also expected to meet deputy foreign minister Abbas Araghchi later the same day.   

Britain is a signatory to the 2015 nuclear deal which saw Iran scale back its nuclear program in exchange for sanctions relief, but the U.S. unilaterally withdrew from the accord last year and reimposed sanctions on Iran. 

Tensions between Washington and Tehran have flared after Iran shot down a U.S. drone on Thursday. 

Iran said the drone violated its airspace – a claim the U.S. denies – near the strategic Strait of Hormuz.  

In response, the U.S. was ready to carry out a military strike against Iran but President Donald Trump said he called it off at the last minute.  

During a visit to Israel, U.S. National Security Adviser John Bolton said on Sunday that Iran is feeling the effects of existing U.S. sanctions as President Trump prepares to impose more sanctions from Monday. 

Trump's made fresh comments on the spat on Saturday saying that he would impose new sanctions on Iran to start Monday, but that he wanted to make a deal to bolster its flagging economy.   

While flagging further sanctions, the president also showed his willingness to make a deal to bolster Iran's economy, an apparent move to defuse tensions following the drone downing.

Iranian President Hassan Rouhani on Sunday hit back the U.S. of stoking tensions in the Gulf through what Iran has called the violation of its airspace by a U.S. military drone, which Tehran shot down, the Fars news agency reported. 

"Rouhani reiterated that this American aggression is the start of new tensions by them in the region," and added: "This region is very sensitive [...] and important to many countries, so we expect international bodies to react appropriately," Fars said.

Iran's Foreign Minister Mohammad Javad Zarif tweeted a map the same day showing a previous border incident with a "spy drone" encroaching its airspace in late May. 

He said the reconnaissance aircraft, a U.S.-made MQ9 Reaper - also widely used for carrying out military strikes - had encroached on Iranian territory on May 26 despite being sent several warnings. 

(With input from AFP, Reuters)