The UK strongly condemned on Monday the killing of 21 Egyptian Copts by the extremist Islamic State group in Libya as barbaric.
It has also vowed to work with regional countries to defeat terrorism.
IS published on Sunday a shocking video purportedly showing the beheading of Coptic Christians it said it had kidnapped recently.
The group pledged to fight what it described as "crusaders."
The UK Prime Minister David Cameron said, in a tweet, the murder of 21 Egyptian Coptic Christians is a “cruel and barbaric act.”
Cameron reiterated that the UK “will not waver in our fight against terrorists and extremism.”
His foreign minister added the UK insists on cooperation with other countries to fight terrorism in the Middle East.
“Such barbaric acts strengthen our determination to work with our partners to counter the expanding terrorist threat to Libya and the region,” the UK Foreign Minister Philip Hammond said.
He continued to say that “Acts of terrorism should not be allowed to undermine Libya’s political transition."
London confirmed that there should not be any role for terrorist groups in the Libya transition.
“We remain fully supportive of the UN’s efforts to build a national unity government for Libya and to bring a political solution to the ongoing security crisis," Hammond said.
"Those who support terrorists can have no part in this process,” he added.
However, the UK government did not comment immediately on Egypt’s air strikes on IS targets in Libya.
The Egyptian army announced on Monday it conducted air strikes against Islamic State jihadists' targets in Libya, including training camps and arms depots.
It said in a statement that the airstrikes were successful in reaching their targets and that the Egyptian fighter jets returned safely to their home bases in Egypt.
These raids came hours after the Egyptian President Abdel-Fattah El-Sisi said that Egypt reserves the right to retaliate against the killing of 21 Egyptians by IS in Libya “at the suitable time and place”.UK government considers killing of Egyptian Copts by IS in Libya as “cruel and barbaric”