Ahmadinejad has accused Israel and western governments for previous killings of scientists [GALLO/GETTY]

Iranian state television has denied that a man killed in his Tehran home on Saturday was a nuclear scientist.

Dariush Rezainejad was shot dead by two men on motorbikes as he entered his garage with his wife and child.

Iranian newspapers first reported that Rezainejad, 35, was working in the country's nuclear programme, which would have made him the fourth nuclear scientist to die or go missing in suspicious circumstances.

On Sunday, state television said he was a masters student in electronics at Khajeh University in Tehran and had worked for the defence ministry, though it was unclear in what capacity.

Ali Larijani, the speaker of parliament, denounced the killing in an address to legislators as the work of Zionists and the United States and said it showed Washington's hostility to Iran.

Larijani has previously served as a negotiator with the West on the country's nuclear programme.

Rezainejad's wife was also wounded and had been taken to a nearby hospital.

'Huge blow'

Al Jazeera's Dorsa Jabbari, reporting from the capital, said: "He [Rezainejad] was entering his garage with his wife at about 4:30 pm local time when two men on motorbikes approached and called him out by his name.

"When he turned around to respond, he was shot in the neck. His wife then ran to get help for her husband, she was chased and also shot.

"What is clear is that this is a huge blow to the country's intelligence units.

"Rezainejad's residence, in the eastern part of the city, was within close proximity of the intelligence ministry headquarters."

Over the past years, several Iranian nuclear scientists have been killed or injured.

In two separate attacks in 2010, Majid Shahriari and Massoud Ali Mohammadi were killed while Feriedoun Abbasi, the current head of Iran's Atomic Energy Organisation, was injured.

Mahmoud Ahmadinejad, the Iranian president, has accused Israel and western governments of being behind the killings of the prominent scientists.

After the death of Shahriari last year, Ahmadinejad said that "undoubtedly the hand of the Zionist regime and western governments is involved'' in the killing.

He said then that the killings would not stop Iran from pursuing its disputed nuclear programme.

Children in Erbil, the capital of Iraq's Kurdistan region, protest against Iranian shelling of border towns [EPA]

At least six soldiers of Iran's elite Revolutionary Guards, including a senior officer, have been killed in clashes with ethnic Kurdish fighters on the border with Iraq, the semi-official Fars news agency says.

Some opposition websites have referred to Abbas Asemi as the most senior commander of the Guards in the important holy city of Qom in southwestern Iran's southwest.

"General Asemi of the Qom branch of the Islamic Revolutionary Guard Corps was killed along with five of his comrades in clashes with terrorist rebels of the PJAK [Party of Free Life of Kurdistan] in the Sardasht area," Fars said on Friday, without giving any further details.

A statement from the Guards confirmed Asemi's death in an explosion but did not say when was killed.

"In recent clashes with PJAK in northwestern Iran, a car belonging to the Revolutionary Guards blew up and some members of the Guards, including Commander Asemi, were killed," the statement said.

Iranian troops launched a major offensive last week against PJAK fighters operating out of rear-bases in neighbouring Iraq.

The autonomous regional government in Iraqi Kurdistan demanded on Tuesday taht Iran respect the border after a Guards commander said Iranian forces had taken "full control" of three PJAK camps inside Iraq.

Rising toll

In Tehran, the commander of the Revolutionary Guards ground forces, Brigadier-General Mohammad Pakpour, demanded Baghdad and the Kurdish regional authorities prevent the fighters from attacking Iran from Iraqi territory.

The fighting had already killed two soldiers - a colonel and a captain - wounded three others, according to security officials in Tehran.

PJAK has said two of its fighters were killed and four wounded. Iranian forces have repeatedly shelled border districts of Iraq's Kurdish region, targeting PJAK bases.

Gun battles and shelling continue in the mountainous border region despite a warning on July 3 by the president of Iraqi Kurdistan, Massoud Barzani, over Iran's cross-border operations.

Earlier this month, a senior Fars quoted an Iranian military official as accusing Barzani of "giving 300,000 hectares of land to the PJAK terrorist group without the knowledge of the central government in Baghdad".

"Iran reserves its right to target and destroy terrorist bases in the border areas," the official was reported as saying.

"This terrorist group carries out operations against the Iranian nation with the support of Iraq's Kurdish regional government."

Like Iraq and Turkey, Iran has a large Kurdish minority, mainly living in northwest and western areas of the Islamic Republic.

Iran and Iraq fought an eight-year war in the 1980s, but since the overthrow in 2003 of Iraq's Saddam Hussein relations have improved.