KABUL (Reuters) - Afghan security officials began investigating Tuesday’s attacks in the capital Kabul and the southern city of Kandahar as the death toll climbed to over 50, including five diplomats from the United Arab Emirates.

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The Ministry of the Interior raised the death toll from the Kabul attack to 38, with 86 wounded, while 13 people were confirmed dead in Kandahar, where the diplomats were killed while on a visit to open an orphanage.

The UAE ambassador and the provincial governor were also wounded in the attack, which killed several other officials including deputy governor Abdul Shamsi.

President Ashraf Ghani spoke by telephone with Sheikh Mohammad bin Zayed Al Nahyan, Crown Prince of Abu Dhabi on Wednesday, expressing condolences and stressing the need to redouble efforts to counter terrorism, a statement said.

The violence highlights the precarious security situation in Afghanistan, which has seen a steady increase in attacks since international troops ended combat operations in 2014, with record numbers of civilian casualties.

Many of the Kabul victims were workers in parliamentary offices who were returning home in the afternoon rush hour or members of emergency services as they were attending victims of an initial blast.

The Taliban, seeking to reimpose Islamic law after their 2001 ouster, claimed responsibility for the attack, which they said targeted a minibus carrying personnel from the National Directorate for Security, Afghanistan’s intelligence agency.

But they denied involvement in the Kandahar attack, set off by a bomb hidden under sofas in the governor’s residence while officials were having dinner. No other group has claimed responsibility.

Ghani’s national security adviser, Hanif Atmar, traveled to Kandahar on Wednesday to launch an investigation.

However Kandahar police chief Abdul Razeq, a feared commander who was in the compound when the explosion occurred but who escaped injury, accused Pakistan’s intelligence services and the Haqqani network, a militant group linked to the Taliban.

He said workers may have smuggled in the explosives during construction work and that a number of people had been held for questioning.

The United Nations condemned the “unprincipled, unlawful and deplorable attacks”, which it said would make peace more difficult to achieve.

“Those responsible for these attacks must be held accountable,” said Pernille Kardel, the U.N. Secretary-General’s Deputy Special Representative for Afghanistan.

Also on Tuesday, seven people were killed in a Taliban attack on a security unit in the southern province of Helmand as violence continued across the country.