Several rockets have struck southern port cities in Israel and Jordan, wounding at least four people.
One rocket exploded in the street in front of the InterContinental Hotel in Aqaba on Monday morning, wounding four Jordanian men, one of them critically, the government there said.
No casualties were reported in the neighbouring Israeli city of Eilat, a resort town that borders Jordan on the east and Egypt's Sinai Peninsula on the west.
An Israeli police official told the Reuters news agency that it is "reasonable to assume" the rockets were fired from the Sinai, the source of an earlier rocket salvo on Eilat in April, the first such attack in five years.
But Egyptian and Jordanian sources each offered contradictory claims about the source of the rocket fire.
An Egyptian security source in the southern Sinai told Al Jazeera the rockets had been fired from Jordan, while Nayef Qadai, Jordan's interior minister, told the AFP news agency that a "preliminary investigation showed that the rocket was fired from
outside Jordanian territory".
Al Jazeera's Nisreen El-Shamayleh, reporting from Amman, said the Jordanian government is "not interested in ruining ties" with Egypt should Sinai be determined as the source of the rocket fire.
"The Jordanians are quite interested in sweeping this under the rug," especially since Eilat, not Aqaba, appeared to be the target of the attack, she said.
Though the attack appeared unsophisticated, it followed a weekend of rocket fire on Israel from the Gaza Strip.
"The country is constantly on the edge," Al Jazeera's Jacky Rowland reported from Jerusalem. "You only need incidents like this to get people panicky."
Gaza blast
The rocket barrage came hours after an early morning explosion devastated the house of a senior Hamas commander in Gaza, wounding at least 31 people, Hamas and medical workers in the Palestinian territory said.
The explosion struck the house of Alaa al-Danaf, a field commander of the Hamas military wing, in the Deir el-Balah refugee camp in southern Gaza, Palestinian security officials said.
At least one person was in critical condition, Al Jazeera's Nicole Johnston reported from Gaza City.
A Hamas medical officer told Al Jazeera the explosion was caused by an Israeli rocket, but an Israeli army spokesman denied responsibility.
It was unclear if al-Danaf was killed in the blast, which occurred at a time of renewed cross-border violence between Palestinian fighters and the Israeli army.
His body was not found in the house after the explosion, Johnston said.
Retaliatory strikes
The explosion badly damaged 12 nearby houses in the refugee camp and rescue teams were digging through the rubble for survivors.
Earlier on Sunday, Binyamin Netanyahu, the Israeli prime minister, issued a strong warning to Hamas leaders in Gaza after a weekend of missile attacks on Israeli communities.
No Palestinian group has claimed responsibility for the violence, which caused damages, but no injuries.
A Hamas commander and rocket-maker was killed in an Israeli air strike at the weekend after a rocket fired from the enclave exploded in the Israeli city of Ashkelon.
Issa Batran, whose caravan was hit by a missile, was the first Hamas commander killed in an Israeli air strike in Gaza since Israel wound up a three-week military offensive against the territory's Hamas rulers in January 2009.
PHOTO CAPTION
A man from Jordan receives treatment in a hospital after being injured.
Al-Jazeera