KABUL (AP) – A suicide car bomber killed seven people and wounded 21 others Wednesday outside a U.S. military base in the same part of eastern Afghanistan where militants stormed government buildings a day earlier, police said.

The militant attacks in Khost, near the tumultuous border with Pakistan, come as the U.S. makes military leadership changes in Afghanistan that demonstrate a clear break from Bush-era appointees.

In Wednesday’s attack, a vehicle drove up to the first gate outside Camp Salerno on the edge of Khost and exploded, said police spokesman Wazir Pacha. U.S. forces confirmed the attack, saying four Afghan security guards were killed and 12 wounded.

There were no casualties among international troops, said Lt. Cmdr. Christine Sidenstricker, a U.S. military spokeswoman.

On Tuesday, 11 Taliban suicide bombers struck government buildings in Khost, sparking gunbattles with U.S. and Afghan forces that killed 20 people and wounded three Americans.

Military analysts say such coordinated attacks are a result of training by Pakistani militants and al-Qaida fighters. In the last year, teams of Taliban militants have launched multipronged assaults on government centers in Kabul, Kandahar and Helmand’s capital.

The stepped up attacks came an Afghan lawmaker said 95 children were among 140 people killed in a U.S.-Taliban clash earlier this month. The U.S. military disputed those numbers, saying condolence payments to the bereaved offered an incentive to exaggerate the death toll in the May 4-5 clash in western Farah province.

U.S. military officials also questioned that no militants were listed despite initial reports from Afghan officials that 25 Taliban were killed.

A list of the dead, with names and ages, was compiled by an Afghan government commission based on the testimony of villagers, said Obaidullah Helali, a lawmaker from Farah and a member of the government’s investigative team.

He said condolence payments were delivered Wednesday to the victims’ families – $2,000 for the dead and $1,000 for the wounded. There were 25 people who were wounded, Helali said.

U.S. military spokesman Col. Greg Julian disputed the figures, saying “there is no physical proof that can substantiate” them. The U.S. has refused to say how many people it thinks died in the clashes.

Julian said a joint U.S.-Afghan investigation team was taken to three different grave sites a day after the clash – one with four mounds, one with 22 mounds and one mass grave that contained an unknown number of bodies.

“The locals couldn’t decide among themselves whether it was 19 or 69 in that mass grave,” Julian said, adding that the dirt displaced from the mass grave seemed to indicate far fewer than 69 bodies were buried there.

This week, President Barack Obama put his stamp on the increasingly bloody eight-year war in Afghanistan by replacing the general in charge of the effort and installing a new ambassador.

The Obama administration hopes the leadership shake-up will help reverse the militants’ momentum. Taliban and other insurgent fighters have increased their attacks the last three years and now control wide swaths of territory.