An Iranian diplomat was killed in Yemen's capital, Sanaa, on Saturday when he resisted gunmen who were trying to kidnap him near the ambassador's residence, the Iranian Foreign Ministry and Yemeni security sources have said.

Iranian Foreign Ministry spokeswoman Marzieh Afkham told Fars News Agency that the diplomat was seriously injured when he resisted his attackers and was taken to a Sanaa hospital, where he died.

"We are seriously following up the dimensions of this terrorist action with the relevant Yemeni government officials," Afkham said.

"Unidentified assailants in a van fired on the diplomat three times as he was leaving the ambassador's residence near a shopping centre in Hadda" - the main diplomatic district of Sanaa - a police source told AFP news agency.

Kidnapping of foreigners in Yemen is common, often carried out by disgruntled tribesmen seeking to press the government to free jailed relatives or to improve public services, or by fighters linked to al-Qaeda.

Another Iranian diplomat, Nour-Ahmad Nikbakht, who was kidnapped in Sanaa last July, remains in captivity.

Sectarian rivalry

Sectarian rivalry between Shia Muslim Houthis and ultra-conservative Sunni Salafis has increased in northern Yemen in the last several months, with at least 210 people killed.

The violence erupted on October 30 when Houthi rebels, who control much of the northern Saada province, accused Salafis in the town of Damaj of recruiting thousands of foreign fighters to prepare to attack them.

Fighting between the two sides in Saada and adjacent provinces stopped as a ceasefire deal took hold a week ago.

That deal gave the Salafis four days to relocate about 250km southwest to the Red Sea port of Hudaida.

The sectarian rivalry has cast a shadow over reconciliation efforts in Yemen, a US-ally that is home to one of the most active wings of the al-Qaeda.

The country, in turmoil since a popular uprising ousted president Ali Abdullah Saleh in 2011, is also facing southern secessionists and an economic crisis.