A roadside bomb killed one Pakistan policeman and wounded three others on Sunday as officers were accompanying a convoy of foreign diplomats, the force said.
The convoy was passing through the town of Malam Jabba in the Swat district when it was hit by an improvised explosive device (IED).
"One policeman succumbed to his wounds while three others were wounded," Swat district police officer Zahidullah Khan told AFP.
"Diplomats were travelling within a police convoy, and the lead police vehicle was impacted," he said, adding that no diplomats were hurt.
Khan said that a trip for foreign diplomats was organised by Islamabad and Swat's Chamber of Commerce to promote the region's local industries, including handicrafts and gemstones.
Another senior police official, Muhammad Ali Khan Gandapur, confirmed the details of the incident.
Envoys from Bosnia and Herzegovina, Portugal, Russia, Kazakhstan, Tajikistan, Turkmenistan, Iran, Rwanda, Zimbabwe and Vietnam were in the convoy, Khan said.
Pakistan's foreign office said the diplomats safely returned to Islamabad.
"Such acts will not deter Pakistan from its commitment towards the fight against terrorism," it said in a statement.
The Russian embassy in Islamabad said their ambassador was in the convoy when it was hit en route to a hotel.
"An escort vehicle hit a mine. Several policemen were injured, diplomats were not harmed," the embassy said on Telegram.
No group has claimed responsibility for the attack, which happened in a region which has been a stronghold of Tehreek-e-Taliban Pakistan (TTP) - a separate group from the Afghan Taliban but with a similar ideology.
Swat - a snow-capped mountain valley split by turquoise waters - is one of Pakistan's most famed beauty spots, but its reputation has a dark side.
In 2012 Malala Yousafzai was shot in the head by the TTP while campaigning as a schoolgirl for education, activism that later earned her the Nobel Peace Prize.
Pakistan has witnessed a dramatic uptick in attacks since the Taliban seized control in 2021 of Kabul.
Islamabad says such offensives are being launched from neighbouring Afghanistan, which the Taliban authorities deny.