Up to 100 people have died in some of Afghanistan's fiercest fighting since US-led forces ousted the Taleban regime in 2001.
Hundreds of UK troops are leading security operations in Helmand
Taleban fighters are battling police in Helmand province where officials say 50 militants and 13 police died.
Coalition and Afghan troops conducted more operations in Kandahar, and say at least 25 militants died in two separate clashes there.
A US national was killed by a suicide bomber in Herat.
Another bomber blew himself up at an Afghan army base in the city of Ghazni as a US military convoy was passing. The bomber and a civilian were killed.
So far this year there have been at least 20 suicide attacks compared with 17 for the whole of 2005 and five in 2004.
Afghan President Hamid Karzai blamed Pakistan's security forces for the fighting, saying they had encouraged insurgents to mount attacks.
Speaking in Kunar near the Pakistani border, he said the Inter Services Intelligence (ISI) trained young Afghans to burn down schools and attack engineers working in construction.
13 police, about 50 Taleban killed in Helmand Province
At least seven militants confirmed dead, possibly another 15-20 in air strike on village of Azizi, Kandahar Province
18 militants and one Canadian soldier killed in Panjwayi district, Kandahar Province
Suicide bomber blows himself up killing US contractor in Herat
Suicide bomber kills himself and civilian in Ghazni
He said Pakistan should realise it could no longer control the future of Afghanistan, as it had in the past.
Pakistan has always strongly denied encouraging militant activity in Afghanistan.
The fighting in Helmand began on Wednesday when Taleban forces stormed the town of Musa Qala.
At least 13 Afghan policemen were killed, along with about 50 Taleban fighters, officials said.
"It was the biggest attack [in Helmand] since the fall of the Taleban," provincial governor Amir Mohammad Akhundzada told Reuters news agency.
Afghan police are now pursuing the militants, with support from international coalition forces.
Meanwhile, the US-led coalition said it had carried out an operation against insurgents in Kandahar.
"Seven members of the Taleban were killed with approximately 15 to 20 more possibly dead from an associated air strike. One coalition member was wounded," a coalition statement said.
The Canadian military said about 18 militants were killed in another part of Kandahar province on Wednesday.
A female Canadian soldier also died, the first woman from the country to die in combat since World War II.
The Taleban have stepped up attacks on foreign and Afghan forces as the Nato-led International Security Assistance Force (Isaf) expands to help the Afghan government with security and reconstruction.
Isaf currently has about 9,000 personnel but plans to build up to about 21,000 troops by November.
Nato spokesman in Afghanistan Mark Laity told the BBC that resistance to the deployment was only to be expected.
"Although the Americans have done a brilliant job down there, a lot of Helmand, Kandahar...all these areas in the south, are effectively ungoverned space," he said.
Britain, which is in charge of security in Helmand, has 3,000 soldiers there.
UK troops were not involved in the Helmand clashes.