Grieving relatives of 96 people killed in the Polish presidential air disaster are in Russia to carry out the grim task of identifying corpses, many of them disfigured beyond recognition.

Polish president Lech Kaczynski’s body was returned to Warsaw on Sunday while his wife Maria Kaczynska was identified on Monday.

However the bodies of dozens of other victims have not been identified, Polish and Russian officials said.

Investigators say they are still searching the crash site for the remains of those who died in the accident in Smolensk, in western Russia.

The Polish health minister says only 14 bodies have been identified by family members.

The identities of another 20 victims have been determined by forensic experts.

DNA testing will be used to identify the remaining dead.

Poland will hold an official memorial service in Warsaw on Saturday for the victims, the country’s senate chief said.

Monday is a national day of mourning in Russia.

Officials there have said there was no technical fault with Mr Kaczynski’s Russian-built plane and that the Polish pilots were flying too low when they tried to land in thick fog on Saturday.

Poland’s chief prosecutor said on Monday there was no evidence at present to suggest the pilot of the doomed plane had been pressured to land.

There has been speculation in some media that Mr Kaczynski himself urged the pilot to land shortly before the ageing Tupolev plane crashed. Traffic controllers had urged the plane not to land.

Victims’ relatives, who are being put up in hotels in Moscow, were starting the identification process at the capital’s municipal morgue where the corpses are being held.

The Polish military chief of staff and heads of the main armed services were also on the crashed plane along with the central bank governor, two deputy ministers, lawmakers and religious and cultural officials.

“The procedure for the relatives to identify the corpses is starting,” said Russian health minister Tatyana Golikova.

“We think that this procedure will last two to three days. We will do everything so this work is organised well and quickly,” she said, adding that counsellors from Poland and Russia were helping the relatives in the ordeal.

Russians paid their respects to the dead by laying flowers and candles outside the Polish embassy in Moscow.

Mr Kaczynski and the presidential delegation died as they were heading to a memorial service at Katyn for 22,000 Polish officers and troops killed by Soviet forces 70 years ago during World War II.