US envoy George Mitchell said on Thursday that opening the Gaza Strip to commercial goods would help to choke off the smuggling that Israel fears could replenish Hamass weapons stocks. But he said the Palestinian Authority of President Mahmoud Abbas must help to supervise the crossings,a demand that has been a major sticking point in Egyptian-brokered negotiations with the Gaza Strips Hamas rulers for a long-term ceasefire. To be successful in preventing the illicit traffic of arms into Gaza,there must be a mechanism to allow the flow of legal goods,and that should be with the participation of the Palestinian Authority, Mitchell said after meeting Abbas. Abbass Western-backed Palestinian Authority holds sway only in the West Bank after Hamas wrested control of the Gaza Strip from his Fatah movement in fighting in 2007. Rocket attacks from Gaza and Israeli air strikes over the past two days have threatened to undermine Mitchells efforts to consolidate a fragile truce between Israel and Hamas that went into effect on January 18,ending 22 days of fighting. Militants launched one rocket from Gaza into Israel late on Wednesday the first since the January 18 ceasefire and another on Thursday. No one was hurt. Israeli aircraft then struck in the southern Gaza Strip,attacking a metal workshop that the military called a weapons factory,causing no casualties; and a motorcycle,wounding two militants and 10 youths passing by,medical workers said. US President Barack Obama dispatched Mitchell on his week-long mission in an early signal of the new administrations commitment to promote Israeli-Palestinian peace talks. Israel has secured US and European pledges to help to prevent Hamas,which it says receives weapons from Iran,from rearming through tunnels under the Gaza-Egypt border and by sea. Egypt has also limited movement through its Rafah crossing with the Gaza Strip. But the tunnels have been the only way for Gazans to get the commercial goods that Israel keeps out,and they have already begun to rebuild the ones that Israeli bombs destroyed. Ismail Haniyeh,Hamass leader in the Gaza Strip,said a ceasefire deal must guarantee the lifting of the siege. Under a 2005 agreement brokered by the United States,the Authority was to help to oversee border crossings. The deal gives Hamas no role. Israeli Prime Minister Ehud Olmert told Mitchell on Wednesday that Israel would not reopen any Gaza crossings,except for aid shipments,until an Israeli soldier captured in 2006 was freed,an Israeli official said.