The strike was launched against Taliban fighters in Nahr-e-Saraj district after their attack on an Afghan National Defense and Security Forces (ANDSF) checkpoint, Colonel Sonny Leggetta, a U.S.-Forces Afghanistan spokesman, tweeted.

"This was a defensive strike to disrupt the attack. This was our first strike against the Taliban in 11 days," he said.

On Feb. 29, Taliban's political chief Mullah Abdul Ghani Baradar and U.S. Special Representative for Afghan Reconciliation Zalmay Khalilzad signed the peace deal in Doha, Qatar.

Under the accord, the United States and NATO will completely pull out their troops from Afghanistan in 14 months, while the Taliban would start an intra-Afghan dialogue.

"To be clear, we are committed to peace, however we have the responsibility to defend our ANDSF partners," said the spokesman.

"Taliban leadership promised the int'l community they would reduce violence and not increase attacks. We call on the Taliban to stop needless attacks and uphold their commitments. As we have demonstrated, we will defend our partners when required."

According to Leggetta, on Tuesday alone, the Taliban conducted 43 attacks on ANDSF checkpoints in Helmand, 555 km south of Kabul.

Earlier in the day, an Afghan special force command, without providing details, said one Taliban key member was killed following an airstrike in Nahr-e-Saraj.

The violence had drastically decreased during a week-long reduction of violence period ending on Feb. 29 when the peace deal was signed.

However, the Taliban militants resumed fighting and clashed with Afghan security forces shortly after the deal was signed.

At least 19 Afghan security force members and several Taliban militants were killed in separate predawn clashes on Wednesday in two northern provinces.