By Nidal al-Mughrabi, Ibrahim Abu Mustafa and Emily Rose CAIRO/GAZA/JERUSALEM (Reuters) – Israel opened a direct crossing for aid into Gaza for the first time in its more than two-month-old war on Hamas on Sunday but also stepped up attacks on the Palestinian enclave, saying military pressure was the only way its hostages would be freed. The Israeli assaults took place amid fierce fighting the length of the coastal strip, according to residents and militants, with communications down for a fourth day, making it hard to reach the wounded. Hopes for peace had been raised on Saturday when a sourc…