At least 14 people, mostly security personnel, were shot dead early Thursday by unidentified gunmen who hijacked passenger buses in Pakistan's southwest Balochistan province, amid intensified security operations against militants in the country.

Security sources in Quetta, capital city of the province, told Xinhua on condition of anonymity that 11 security personnel, including nine from Pakistan navy, one from Pakistan coast guards, and one from Pakistan air force, were among the victims whereas identities of the remaining three victims had not been determined yet.

The sources added that around 20 armed men wearing the attire of security forces stopped up to five passenger vehicles at Buzi Top on the Makran Coastal Highway and checked identity cards of the passengers.

The militants forcibly removed 14 people from different buses heading towards the southern port city of Karachi and allowed others to leave. After receiving the information of abduction, security forces rushed to the site but militants had already managed to flee away after killing all the abductees.

Later on Thursday, Baloch Raaji Aajoi Sangar, a militant group, claimed the attack on its unverified social media account, but officials did not confirm it. The security forces have cordoned off the area and launched an extensive operation against the culprits.

Pakistani President Arif Alvi and Prime Minister Imran Khan condemned the attack, saying that such cowardly attempts to spread disunity in the country could never succeed and the nation was united and steadfast in its fight against terrorism.

Khan sought investigation into the incident and directed the departments concerned to make every possible effort to identify and bring the perpetrators of the barbaric act to justice, a statement from the Prime Minister Office said.

Since the start of April, Pakistan has witnessed a slight surge in terrorist attacks in different areas of the country. Thursday's incident is a major terrorist attack during the past 18 days.

On Friday last week, a suicide bomber attacked a fruit and vegetable market in Balochistan's provincial capital of Quetta and killed 20 people while leaving dozens of others wounded.

During his visit to Quetta to condole grieved families on Tuesday, President Alvi vowed to speed up the ongoing campaign against terrorism to eliminate the menace for peace, stability and progress of the country.

Pakistan army, police and paramilitary forces claimed to have accelerated their intelligence-based operation to eliminate the terrorists and arrest their aids hiding in the rural as well as in the urban areas.

On Tuesday, Pakistan army and police conducted an operation and killed five terrorists of Pakistani Taliban hiding in a house in Peshawar in northwestern Pakistan.

According to security forces, the terrorists were planning to attack some targets in the province as a huge cache of weapons and explosive devices was found from them.

Director of Islamabad Council for International Affairs Saeed Chaudhry told Xinhua that the ongoing wave of terrorism was very dangerous because the peace the country achieved after a long struggle was under threat now.

"During last three weeks, we saw a strange and meaningful trend of terrorism when all the terrorist groups look involved in different acts. We feel that the current acts of terrorism are being conducted by the coordination among different groups," said Chaudhry.

Pakistani Foreign Minister Shah Mahmood Qureshi has already told media that the government had reliable reports about some possible terrorist attacks in April.

Analysts urged the government as well as law enforcement agencies to form a comprehensive policy and start a new operation against militancy and extremism across the country.

In December 2014, the Pakistani parliament passed a National Action Plan against terrorism and extremism after around 150 people were killed in a terrorist attack at a school in Peshawar.

According to local reports, Khan is likely to visit Quetta on Sunday to look into the security situation of the province following two deadly attacks in one week.