Updated at 6 p.m. Eastern

Two U.S. service members were killed Wednesday in a suicide car bomb attack on a NATO convoy near Kandahar in southwestern Afghanistan, Pentagon officials said.

Several other troops were wounded in the attack, but the number of wounded and their nationalities were not immediately disclosed.

The Taliban claimed responsibility for the attack near the airfield on the outskirts of Kandahar, the group's spiritual birthplace.

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An early statement from NATO said only, "Resolute Support can confirm that a NATO convoy was attacked this afternoon in Kandahar. The attack did cause casualties."

Local reports said a suicide bomber drove a vehicle rigged with explosives into the convoy that was part of the NATO Resolute Support mission in Afghanistan as it headed to the airfield, a major hub of operations for international troops in the region.

In a separate incident Wednesday, a U.S. service member was killed in a non-combat-related incident in Kuwait, according to a statement from Combined Joint Task Force-Operation Inherent Resolve, the mission against the Islamic State of Iraq and Syria, or ISIS.

"Further information will be released by the relevant national authorities 24 hours after the next of kin have been notified," it stated.

Pressure for a New Afghan Strategy

The attack on the convoy brought to 11 the number of U.S. service members who have died in Afghanistan this year. In 2016, a total of 14 U.S. troops were killed.

Since the nation's longest war began in 2001, at least 2,400 U.S. service members have been killed in and around Afghanistan, according to the website icasualties.org.

The suicide attack, the overall deteriorating security situation in Afghanistan, and the wave of attacks by the Taliban and the ISIS offshoot called Islamic State-Khorasan Province, are expected to lend urgency to White House and Pentagon deliberations on a new strategy for the region, which could involve sending in additional troops.

The Taliban's summer offensive has hit district headquarters, government officials, minority groups and the Afghan National Defense Security Forces with increasing frequency.

The convoy attack came as Afghan authorities in western Herat province bordering Iran tightened security ahead of a mass funeral for the victims there of an attack on a mosque the previous evening that killed at least 32 and was claimed by the Islamic State-Khorasan Province, or IS-K.

Another 66 worshippers were injured in the assault by a suicide bomber who sprayed bullets at security guards before detonating his explosives, local authorities said.

On Monday, IS-K claimed responsibility for an attack on the Iraqi Embassy in Kabul and, on Wednesday, the Taliban claimed responsibility for ambushing and killing Jaghatu District Gov. Manzur Hussain and a passenger in his car.

On Tuesday, two U.S. soldiers were injured when their Black Hawk helicopter made a hard landing in the IS-K stronghold in the Achin District of eastern Nangarhar province.

Dire Situation

Also on Tuesday, the office of the Special Inspector General for Afghan Reconstruction (SIGAR) issued its quarterly report to Congress detailing the dire situation faced by the allies and the central government of President Ashraf Ghani.

From January 1, 2017, through May 8, 2017, there were 2,531 ANDSF service members killed in action and an additional 4,238 wounded in action, the report said. In addition, the poppy trade that supports the Taliban is flourishing.

"The estimated value of opiates produced in Afghanistan increased to $3.02 billion in 2016 from $1.56 billion in 2015," the report said.

At the same time, the costs to the U.S. and its coalition allies continue to rise. According to SIGAR's analysis, the U.S. has obligated an estimated $714 billion for all spending -- including war fighting and reconstruction -- in Afghanistan over more than 15 years.

In the spring, Defense Secretary Jim Mattis used trips to Europe to round up support from NATO allies to increase spending on Afghanistan and possibly add to their own troop contingents there.

In June, President Donald Trump authorized Mattis to set the Force Management Level, or troop level, in Afghanistan after granting him similar authority in Iraq and Syria.

Mattis had pledged to deliver a new strategy for Afghanistan by mid-July that would rely on increased air power and would also address the long-standing request of Army Gen. John Nicholson, commander of U.S. Forces-Afghanistan and the NATO Resolute Support Mission, for an additional 3,000 to 5,000 troops.

However, the Mattis plan has been held up as the White House reviews the entire Afghanistan mission amid reports that top advisers to Trump have been recommending a scaled-down U.S. operation.

An Unsalvageable Mission?

Long-time analysts of the Afghanistan situation have become increasingly doubtful that the mission can be salvaged.

"There is a case for a deliberate U.S. withdrawal from Afghanistan," analyst Anthony Cordesman said in a commentary for the Center for Strategic and International Studies.

His comments echoed the refrain of U.S. advisers in Afghanistan since the start of the war in 2001: "The Afghan government remains divided and weak, its security forces will take years of expensive U.S. and allied support to become fully effective, and they may still lose even with such support."

He said that the Trump administration "should consult with Congress, seek a clear legislative mandate for staying if it decides this is the proper course, and openly and transparently explain its decisions to the American people. But it cannot simply sit and wait, take token action, and issue more empty words without losing the war."

-- Richard Sisk can be reached at Richard.Sisk@Military.com.