KABUL, Afghanistan — A multi-pronged militant assault on a small, remote American base killed nine American soldiers and wounded 15 today in the deadliest attack on American forces in Afghanistan in three years, officials said.

The attack on the American outpost came the same day a suicide bomber targeting a police patrol killed 24 people, while American coalition and Afghan soldiers killed 40 militants elsewhere in the south.

The militant assault on the American troops began around 4:30 a.m. in a dangerous region close to the Pakistan border and lasted throughout the day.

Militants fired machine guns, rocket-propelled grenades, and mortars from homes and a mosque in the village of Wanat in the mountainous northeastern province of Kunar, NATO’s International Security Assistance Force said in a statement.

Nine American troops were killed in the attack, a Western official said on condition of anonymity because he was not authorized to release the troops’ nationalities.

NATO confirmed nine of its soldiers had been killed and 15 wounded. Four Afghan soldiers also were wounded, NATO said.

“Although no final assessment has been made, it is believed insurgents suffered heavy casualties during several hours of fighting,” NATO said in a statement.

The top American military spokeswoman in Afghanistan, Lieutenant Colonel Rumi Nielson-Green, said she could not comment because the fight was ongoing.

The attack appeared to be the deadliest for American troops in Afghanistan since June 2005, when 16 American troops were killed — also in Kunar province — when their helicopter was shot down by a rocket-propelled grenade.

Those troops were on their way to rescue a four-man team of Navy SEALs caught in a militant ambush. Three SEALs were killed, the fourth was rescued days later by a farmer.

Today’s attack came during a period of rising violence in Afghanistan. Monthly death tolls of American and NATO troops in Afghanistan surpassed American military deaths in Iraq in May and June. Last Monday, a suicide bomber attacked the Indian Embassy at Kabul, killing 58 people in the deadliest attack at the Afghan capital since 2001.

In two other incidents this month, an Afghan government commission found that American aircraft killed 47 civilians during a bombing run in Nangarhar province, while a separate incident in Nuristan province is alleged by an Afghan officials to have killed 22 civilians.

The high casualty tolls have prompted the International Committee of the Red Cross this week to ask all sides to show restraint and avoid civilian casualties. But violence continued around the country today.

A suicide bomber on a motorcycle blew himself up next to a police patrol today at the southern province of Uruzgan, killing 24 people.

The bomb attack on a police patrol at a busy intersection of the Deh Rawood district killed five police officers and 19 civilians, wounding more than 30 others, Uruzgan’s police chief, Juma Gul Himat, said. Most of those killed and wounded were shopkeepers and young boys selling goods in the street, he said.

Elsewhere, Taliban militants executed two women in central Afghanistan late yesterday after accusing them of working as prostitutes on an American base.

The women, dressed in blue burqas, were shot and killed just outside Ghazni city in central Afghanistan, a spokesman for Ghazni’s governor, Sayed Ismal, said. He called the two “innocent local people.”

Taliban fighters told Associated Press Television News the two women were executed for allegedly running a prostitution ring catering to American soldiers and other foreign contractors at an American base at Ghazni city.

A U.S. military spokesman, 1st Lieutenant Nathan Perry, said he had not heard allegations “anything close to that nature.”

Meanwhile, at least 40 militants were killed following an attack on Afghan and American-led coalition forces at Helmand province, the coalition said in a statement.

The militants attacked the combined forces near Sangin yesterday from “multiple concealed and fortified positions,” the coalition said. Thirty “enemy boats” and several small bridges have been destroyed on the Helmand River during two days of fighting, it said.

A soldier with NATO’s International Security Assistance Force died in a roadside blast at Helmand province today, a statement said. The soldier’s nationality was not released and it wasn’t clear if the death was connected to the two-day battle.

More than 2,300 people — mostly militants — have died in insurgency related violence this year, according to an Associated Press tally of official figures.

In the country’s north, a soldier serving with ISAF died of wounds caused by an explosion yesterday, the military alliance said in a statement. The statement did not give any further details of the explosion. The soldier’s nationality was not been disclosed.

There are nearly 53,000 troops from 40 nations serving the ISAF in Afghanistan.