"British nationals should contact their airline"
UK citizens have been warned not to travel to parts of India and Pakistan as tensions escalate.
At least 26 people were killed and 46 wounded after India launched missile strikes into Pakistani-controlled territory, hitting six locations.
The attacks came weeks after more than two dozen tourists were killed in Kashmir, which India has blamed on Pakistan-backed militants. Pakistan has denied any involvement.
The Foreign, Commonwealth and Development Office (FCDO) updated its travel advice.
It warned against all travel within 10 kilometres of the India-Pakistan border, within 10 miles of the Line of Control in Kashmir, and to Pakistan’s Balochistan province.
In a statement, the FCDO said: “On the night of 6 May (UK Time), the Indian Ministry of Defence stated it had struck nine sites in Pakistan and Pakistan-administered Kashmir.
“In response, there are reports of Pakistani artillery fire across the Line of Control.
“On the night of 6 May (UK Time) Pakistan Civil Aviation Authority indicated that it was closing Pakistan airspace for at least 48 hours. There are reports of flights being diverted.
“British nationals should contact their airline for up-to-date information. We are continuing to monitor the situation closely.
“British nationals should stay up to date with our travel advice and follow the advice of local authorities.”
The UK government also warned of possible disruptions inside India due to a planned Civil Defence drill.
The FCDO added: “According to media reports on 6 May, the Indian Government announced a Civil Defence mock drill on 7 May in several states across India.
“The drill may include temporary power cuts or blackouts, loud air raid sirens, suspension of mobile signals, or traffic diversions.
“Authorities may also conduct evacuation exercises or hold public announcements.”
India said its strikes targeted militant infrastructure linked to the tourist killings.
Pakistani officials said the missiles hit at least two locations tied to banned groups.
Meanwhile, the Indian army said seven civilians died in Kashmir following retaliatory Pakistani shelling.
Pakistan’s Prime Minister Shehbaz Sharif condemned the strikes and accused India of launching “cowardly attacks”.
“Pakistan has every right to give a robust response to this act of war imposed by India, and a strong response is indeed being given.”
He has called an emergency meeting of the National Security Committee.
Political leaders in the UK have expressed alarm at the violence.
Scotland’s First Minister John Swinney said:
“I am deeply concerned by the events in Kashmir tonight and urge calm and dialogue to avoid further conflict.”
Labour MP Stella Creasy said: “Deeply concerning to see military air strikes in Jammu Kashmir tonight by the Indian Government.
“Restraint by all concerned must be sought and secured.”