Tensions in Jerusalem sparked the worst round of cross-border violence between Israel and extremists in the Gaza Strip in months on Saturday. At least 30 rockets were fired into Israel, while the Israeli military struck back at Hamas positions. Skirmishes have increased in recent days in Jerusalem, where residents are bracing for possible further unrest, as police stepped up security and the US embassy appealed for calm. On Friday, Israeli police said 44 people were arrested and 20 officers were wounded in chaotic scenes in Jerusalem the previous night. Security forces clashed separately with Palestinians angry about Ramadan restrictions and Jewish extremists who held an anti-Arab march nearby. The incidents in Jerusalem triggered a flare-up of hostilities in Gaza. The armed wing of Hamas warned Israel "not to test" its patience and extremists in the Palestinian enclave started firing rockets into southern Israel late on Friday and continued through Saturday morning. The Israeli military said its aircraft and tanks struck back at rocket launchers and unspecified underground infrastructure. While the Hamas armed wing did not claim responsibility for the rocket attacks, a small military formation affiliated with the leftist Popular Front for the Liberation of Palestine said it had fired some. Sirens warning of incoming rockets from Gaza blared continually in southern Israel. Air defences intercepted some of the rockets. There were no reports of injuries on either side. At dawn, hundreds of people in Gaza challenged nightly curfews imposed by Hamas to curb the coronavirus outbreak and took to the streets in an act of solidarity with fellow Palestinians in Jerusalem, burning tyres. On Friday, there had been concerns that earlier violence could re-ignite following noon prayers at Al Aqsa Mosque in Jerusalem, but thousands of worshippers dispersed peacefully after Muslim religious leaders called for restraint. However, in the evening, dozens of Palestinians marched towards an entrance to the walled Old City of Jerusalem and clashed with police, who said the protesters had thrown stones at officers. Six Palestinians were injured, with two admitted to hospital. Palestinians have clashed with Israeli police on a nightly basis since the start of Ramadan. The tensions began when police placed barricades outside the Old City's Damascus Gate, where Muslims traditionally gather after the daytime fast. The clashes intensified on Thursday evening when hundreds of Palestinians hurled stones and bottles at police, who fired a water cannon and stun grenades to disperse them. Dozens of Palestinians were wounded. At the same time, a far-right Jewish group known as Lahava led a march of hundreds of protesters chanting “Arabs get out” towards the Damascus Gate. Police used water cannon, stun grenades and mounted officers to push the far-right protesters back. Early on Saturday, Jordan strongly condemned "the racist attacks on Palestinians". Foreign Minister Ayman Safadi tweeted: "As the occupying power under international law, Israel is responsible for stopping these attacks and for the dangerous consequences of failing to do so." The US embassy said it was "deeply concerned" by the violence in recent days. "We hope all responsible voices will promote an end to incitement, a return to calm, and respect for the safety and dignity of everyone in Jerusalem," it said. Tens of thousands of Palestinians attended weekly prayers at the Al Aqsa Mosque compound in Jerusalem’s Old City on Friday. Sheikh Muhammad Hussein, the Grand Mufti of Jerusalem, condemned the “police and settlers’ attack on Palestinians in Jerusalem” in his sermon. He called on worshippers to remain calm and not to give the other side an excuse to storm the compound. They dispersed peacefully after prayers and there were no immediate reports of unrest. The sprawling hilltop compound has seen clashes on a number of occasions over the years and was the epicentre of the 2000 Palestinian intifada, or uprising.