Pakistani and Afghan officials say their forces have launched multiple strikes at each other in cross-border clashes, with each side claiming to have killed dozens more enemy troops in what has been the deadliest fighting yet between the two neighbors.

Pakistan and Afghanistan have traded attacks in a dramatic escalation of tensions between the countries.

Pakistani officials say a suicide bomber targeted a Shiite mosque on the outskirts of Islamabad during Friday prayers, killing 31 people and wounding at least 169 others.

Officials say the closure of border crossings for bilateral trade between Afghanistan and Pakistan has extended into a second day after deadly weekend clashes spiked tensions.

Pakistan’s defense minister says that his nation’s nuclear program “will be made available” to Saudi Arabia if needed under the countries’ new defense pact.