KABUL (AP) ― Suicide bombers launched multiple attacks in a remote corner of southwestern Afghanistan near the Iranian border Tuesday, killing dozens of people including shoppers buying sweets for a Muslim holiday and leaving charred and smoldering bits of cookies and dried fruit among the bodies on the ground.

A separate market bombing, this one in northern Afghanistan, brought the overall death toll to 46, most of whom were civilians. It was the deadliest day for Afghan civilians this year.

The attacks in provinces on opposite ends of the country ― Nimroz in the southwest and Kunduz in the north ― come as Taliban insurgents and their allies step up their assaults in a display of force that often results in civilian carnage. Militants are especially trying to weaken the still-developing Afghan security forces, who are to assume control of security across their homeland in 28 months when most foreign combat troops will have left.

“The Taliban “want to expand their influence ― show that they are everywhere,” said Afghan political analyst Jawid Kohistani. “They want to show that the Afghan police are not strong enough so they are targeting the security forces and the government.”

The scope of the attacks in Nimroz, which has seen relatively few insurgent attacks over the past year, was surprising. The bombings took place in the provincial capital, Zaranj, where militants wearing suicide vests detonated their explosives in various neighborhoods, provincial police chief Musa Rasouli said. At least 25 civilians and 11 police were killed, he said.

The Nimroz provincial capital lies about 10 kilometers from the Iranian border. Police arrested three attackers who later apparently confessed that they were from Zahedan, the capital of Iran’s Sistan and Baluchistan province near the Afghan border, according to Sadeq Chakhansori, a member of the Nimroz provincial council. The significance of this was not immediately clear.

Authorities said the casualties would have been far higher had they not learned of the plot beforehand. Police killed two potential attackers Monday night and captured three more Tuesday morning. But they could not catch them all.

Rasouli said three suicide bombers detonated their explosive vests, including one in front of a television station and another at an intersection in a bazaar. Most of the casualties, however, were from a bombing in a shopping bazaar in front of a civilian hospital. The area was crowded with shoppers from the city and outlying areas who were buying dried fruit, cookies and other sweets for the coming Muslim holiday of Eid.

“It was very powerful,’’ Rasouli said. “Everywhere there was smoke. With my eyes, I saw the dead bodies.’’

The bodies, wrapped in blood-stained sheets, were ferried off in ambulances and pickup trucks. The legs of two victims hung off the back of a small truck that sped away with a long sheet dragging behind in the dusty road. Police fired bullets into the air to clear crowds from the scene.

“We cannot carry on with our daily lives,’’ Sayed Ahmad said, lying on a bed in a hospital where he was being treated for injuries. “People are scared and cannot go out of their houses,’’ he said. “We don’t know what to do.”

Three more attackers, also clad in explosive vests, tried to strike the governor’s house, but Afghan police killed them before they were able to blow themselves up.

“We took off their suicide vests ― very carefully, very professionally ― after we killed them,’’ Rasouli said. “They had no chance, the police bullets rained on them.’’

The sparsely populated province is partly desert and is not regularly beset by insurgent attacks as are Helmand and Kandahar provinces to the east. Recently, however, Nimroz has seen an increase in violence. On Saturday, an Afghan police officer killed 11 of his fellow officers in the remote Dilaram district of the province.

Tuesday’s other major attack, in northern Kunduz province, involved a bomb on a motorcycle that was parked outside a crowded bazaar in Archi district. The attack killed at least 10 people, including five children, and wounded at least 25 others, according to Hamid Agha, the police chief for Archi district.

Altogether, at least 35 civilians were killed in the attacks in the two provinces, making Tuesday the deadliest day for Afghan civilians this year.

“What we saw today were further acts of intentional mass murder,” said Gen. John Allen, the top commander of U.S. and NATO forces in Afghanistan. “By targeting innocent civilians in populated areas, the insurgents have again shown they will kill non-combatants without hesitation to advance their backward-looking plans for Afghanistan. Once again, I call on (Afghan Taliban leader) Mullah Omar to rein in his murderers. His intentions not to target civilians are hollow,” Allen said in a statement.

In past statements, Omar has asked his fighters to avoid civilian casualties. In one message in 2010, for instance, he said: “Pay attention to the life and property of the civilians so that ... your jihad activities will not become a cause for destruction of property and loss of life of people.”

The U.N. reported last week that civilian deaths were lower in the first six months of 2012 than in the first half of 2011, but that an onslaught of summer attacks from insurgents were threatening to reverse that trend. In all, 1,145 civilians were killed in Afghanistan between January and June of this year, according to the U.N. report.

On June 6, a car bomb and a motorcycle bomb killed 22 people near Kandahar airport in the volatile south. Another suicide attack July 14 on a wedding killed 23 people, including the provincial intelligence chief and two army generals.