MOSCOW, October 28 (RIA Novosti) - The Pakistani market blast that claimed 90 lives on Wednesday might have been triggered by the visit of the U.S. Secretary of State or tensions in neighboring Afghanistan, a Russian expert said.

The death toll in Wednesday morning's blast in Peshawar has so far risen to 90 people, with more than 200 wounded, according to the latest media reports.

"There may be several causes. The first is certainly [Hillary] Clinton's visit," said Professor Vladimir Moskalenko from the Institute for Oriental Studies at the Russian Academy of Sciences.

In a briefing with reporters, Clinton, who arrived in Islamabad earlier on Wednesday for a three-day visit, said her trip would expand cooperation with Pakistan beyond the military sphere and stressed that she would be reaching out to the country's broadly anti-American public with extensive media engagements.

Moskalenko said Clinton's visit came amid high anti-American sentiments in Pakistan and that it "naturally" provoked anger and resentment.

"The second is that Pakistan and Afghanistan are connected. Afghanistan is currently seeing a wave of terror ahead of the runoff of presidential polls," Moskalenko said.

Six foreigners were killed and another five wounded in an attack on a guest house used by UN staff in the center of the Afghan capital on Wednesday morning.

Another hotel in Kabul also came under rocket attack on Wednesday, no casualties have been reported.

The Russian expert said another reason behind the Peshawar blast could be the increasing protests against military operations in the northern Pakistani region of Waziristan on the border with Afghanistan.